bluuebunny/crossref_metadata_2025 huggingface dataset:
Nested-multiplex PCR detection of Orthopoxvirus and Parapoxvirus directly from exanthematic clinical samples
Authors: Abrahão Jônatas S , Lima Larissa S , Assis Felipe L , Alves Pedro A , Silva-Fernandes André T , Cota Marcela MG , Ferreira Vanessa M , Campos Rafael K , Mazur Carlos , Lobato Zélia IP , Trindade Giliane S , Kroon Erna G
Published: September 2009

Background

Orthopoxvirus(OPV) andParapoxvirus(PPV) have been associated with worldwide exanthematic outbreaks. Some species of these genera are able to infect humans and domestic animals, causing serious economic losses and public health impact. Rapid, useful and highly specific methods are required to detect and epidemiologically monitor such poxviruses. In the present paper, we describe the development of a nested-multiplex PCR method for the simultaneous detection of OPV and PPV species directly from exanthematic lesions, with no previous viral isolation or DNA extraction.

Methods and Results

The OPV/PPV nested-multiplex PCR was developed based on the evaluation and combination of published primer sets, and was applied to the detection of the target pathogens. The method showed high sensitivity, and the specificity was confirmed by amplicon sequencing. Exanthematic lesion samples collected during bovine vaccinia or contagious ecthyma outbreaks were submitted to OPV/PPV nested-multiplex PCR and confirmed its applicability.

Conclusion

These results suggest that the presented multiplex PCR provides a highly robust and sensitive method to detect OPV and PPV directly from clinical samples. The method can be used for viral identification and monitoring, especially in areas where OPV and PPV co-circulate.
Identification of biology-based breast cancer types with distinct predictive and prognostic features: role of steroid hormone and HER2 receptor expression in patients treated with neoadjuvant anthracycline/taxane-based chemotherapy
Authors: Darb-Esfahani Silvia , Loibl Sibylle , Müller Berit M , Roller Marc , Denkert Carsten , Komor Martina , Schlüns Karsten , Blohmer Jens Uwe , Budczies Jan , Gerber Bernd , Noske Aurelia , du Bois Andreas , Weichert Wilko , Jackisch Christian , Dietel Manfred , Richter Klaus , Kaufmann Manfred , von Minckwitz Gunter
Published: September 2009

Introduction

Reliable predictive and prognostic markers for routine diagnostic purposes are needed for breast cancer patients treated with neoadjuvant chemotherapy. We evaluated protein biomarkers in a cohort of 116 participants of the GeparDuo study on anthracycline/taxane-based neoadjuvant chemotherapy for operable breast cancer to test for associations with pathological complete response (pCR) and disease-free survival (DFS). Particularly, we evaluated if interactions between hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2) expression might lead to a different clinical behavior of HR+/HER2+ co-expressing and HR+/HER2- tumors and whether subgroups of triple negative tumors might be identified by the help of Ki67 labeling index, cytokeratin 5/6 (CK5/6), as well as cyclooxygenase-2 (COX-2), and Y-box binding protein 1 (YB-1) expression.

Methods

Expression analysis was performed using immunohistochemistry and silver-enhanced in situ hybridization on tissue microarrays (TMAs) of pretherapeutic core biopsies.

Results

pCR rates were significantly different between the biology-based tumor types (P = 0.044) with HR+/HER2+ and HR-/HER2- tumors having higher pCR rates than HR+/HER2- tumors. Ki67 labeling index, confirmed as significant predictor of pCR in the whole cohort (P = 0.001), identified HR-/HER- (triple negative) carcinomas with a higher chance for a pCR (P = 0.006). Biology-based tumor type (P = 0.046 for HR+/HER2+ vs. HR+/HER2-), Ki67 labeling index (P = 0.028), and treatment arm (P = 0.036) were independent predictors of pCR in a multivariate model. DFS was different in the biology-based tumor types (P < 0.0001) with HR+/HER2- and HR+/HER2+ tumors having the best prognosis and HR-/HER2+ tumors showing the worst outcome. Biology-based tumor type was an independent prognostic factor for DFS in multivariate analysis (P < 0.001).

Conclusions

Our data demonstrate that a biology-based breast cancer classification using estrogen receptor (ER), progesterone receptor (PgR), and HER2 bears independent predictive and prognostic potential. The HR+/HER2+ co-expressing carcinomas emerged as a group of tumors with a good response rate to neoadjuvant chemotherapy and a favorable prognosis. HR+/HER2- tumors had a good prognosis irrespective of a pCR, whereas patients with HR-/HER- and HR-/HER+ tumors, especially if they had not achieved a pCR, had an unfavorable prognosis and are in need of additional treatment options.

Trial registration

ClinicalTrials.gov identifier: NCT00793377
Land and Succession in the Indigenous Noble Houses of Sixteenth-Century Tlaxcala
Authors: Hicks Frederic
Published: September 2009

On the eve of the Spanish conquest, and in the decades immediately thereafter, the indigenous population of Tlaxcala, in the Valley of Puebla, east of the Basin of Mexico, was grouped into four kingdoms (tlahtocayotl or altepetl, generally called cabeceras in Spanish) of pre-Hispanic origin. Within each cabecera, the basic social and political units were lordly houses (teccalli), each headed by a lord (teuctli) and including junior nobles and nonnoble commoners who worked the lands of the house and provided it with other services. The proceedings of a number of early colonial legal cases indicate that the lands of a teccalli were of two kinds: collectively held lands of the teccalli as a whole and individually held lands of particular nobles of the house. Collectively held lands were passed down over generations undivided and served to maintain the integrity and power of the house. Individually held lands, which were held by women as well as men, were frequently transferred from one house to another and recombined upon marriage, linking the noble houses; they served to maintain the unity and power of the state as a whole.
Baptism among the Salinan Neophytes of Mission San Antonio de Padua: Investigating the Ecological Hypothesis
Authors: Peelo Sarah
Published: September 2009

The motivations for relatively rapid incorporation of Native Californian populations into the Spanish mission system are the subject of anthropological and historical debate (e.g., S. Cook 1976; Coombs and Plog 1977; Duggan 2000; Guest 1979; Hackel 2005; Jackson 1999; Larson, Johnson, and Michaelsen 1994; Milliken 1995; Sandos 1991, 1998, 2004). The ecological hypothesis is one of many explanations offered. Advocates of this hypothesis maintain that environmental push factors such as drought, depletion of native food sources by the grazing of livestock, and environmental changes induced by the construction of irrigation systems and pull factors such as the potential food sources provided by the missions were motivating reasons for the rapid incorporation of native peoples into the Spanish mission system of Alta California. This hypothesis has predominantly been used by scholars to explain Chumash baptism in southern California missions (Coombs and Plog 1977; Jackson 1999; Larson, Johnson, and Michaelsen 1994), but has more recently also been used to discuss Esselen and Costanoan/Ohlone baptisms at Mission San Carlos (Hackel 2005). In this paper, I examine the validity of the ecological hypothesis for Salinan Indian baptism at Mission San Antonio de Padua using documentary and archaeological evidence. Salinan Indians at Mission San Antonio were influenced by only some environmental push and pull factors, and only at specific times during this culture contact period. As economics, culture, and environment changed through time at Mission San Antonio, the reasons that Salinan peoples chose baptism may also have been dynamic. This conclusion emphasizes that the reasons Native Californians chose baptism are geographically, temporally, and culturally contingent.
Kidins220/ARMS downregulation by excitotoxic activation of NMDARs reveals its involvement in neuronal survival and death pathways
Authors: López-Menéndez Celia , Gascón Sergio , Sobrado Mónica , Vidaurre Oscar G. , Higuero Alonso M. , Rodríguez-Peña Ángeles , Iglesias Teresa , Díaz-Guerra Margarita
Published: September 2009

Functional and protein interactions between the N-methyl-D-aspartate type of glutamate receptor (NMDAR) and neurotrophin or ephrin receptors play essential roles in neuronal survival and differentiation. A shared downstream effector for neurotrophin- and ephrin-receptor signaling is kinase D-interacting substrate of 220 kDa (Kidins220), also known as ankyrin repeat-rich membrane spanning (ARMS). Because this molecule is obligatory for neurotrophin-induced differentiation, we investigated whether Kidins220/ARMS and NMDAR functions were related. Here, we identify an association between these proteins and discover that excitotoxicity, a specific form of neuronal death induced by NMDAR overstimulation, dramatically decreases Kidins220/ARMS levels in cortical neurons and in a model of cerebral ischemia. Kidins220/ARMS downregulation is triggered by overactivation of NMDARs containing NR2B subunits and subsequent Ca2+ influx, and involves a dual mechanism: rapid cleavage by the Ca2+-dependent protease calpain and calpain-independent silencing of Kidins220/Arms gene transcription. Additionally, Kidins220/ARMS knockdown decreases ERK activation and basal neuronal viability, and enhances neuronal death under excitotoxic conditions. Our results demonstrate Kidins220/ARMS participation in neuronal life and death pathways, and constitute the first report of its regulation under pathological conditions.
Successful Use of Dexmedetomidine for Sedation in a 24-Week Gestational Age Neonate
Authors: O'Mara Keliana , Gal Peter , Ransom J Laurence , Jr John E Wimmer , Carlos Rita Q , Dimaguila Mary Ann VT , Davonzo Christie , Smith McCrae
Published: September 2009

Objective:

To describe a case of dexmedetomidine use for sedation in a 24-week gestational age premature neonate.

Case Summary:

A 9-day-old, 24-week gestational age male neonate on high-frequency oscillatory mechanical ventilation was experiencing severe agitation refractory to high-dose intravenous narcotics and benzodiazepines. Since the infant's respiratory stability was reliant on adequate sedation, he was given dexmedetomidine after several days of suboptimal response to escalation of standard agents. Treatment prior to dexmedetomidine included continuous-infusion fentanyl 10 μg/kg/h, intravenous lorazepam 0.6 mg/kg every 4 hours, intermittent doses of both lorazepam and midazolam as needed, and a single bolus dose of phenobarbital. The patient calmed markedly during the dexmedetomidine loading dose infusion and remained adequately sedated while the drug was continued. The dexmedetomidine infusion allowed weaning of mechanical ventilation settings and eventual extubation of the infant, as well as rapid tapering of other sedative medications. The maximum dexmedetomidine infusion rate was 0.7 μg/kg/h, and total duration of therapy was 19 days. No significant adverse effects were directly attributed to dexmedetomidine use during this time.

Discussion:

Dexmedetomidine is a novel α2-agonist approved for short-term sedation in mechanically ventilated adults. Data describing its use in pediatric and neonatal patients continue to emerge. The prolonged use of dexmedetomidine in very-low-birth-weight neonates has not been described in the literature.

Conclusions:

Dexmedetomidine was an effective sedative and analgesic in a 24-week gestational age neonate treated for refractory agitation while on mechanical ventilation. Based on its documented efficacy for pain and sedation and its favorable adverse effect profile, dexmedetomidine warrants further study as first-line or adjunct therapy with narcotics for sedation in ventilated newborns.
Gelatin In Situ Zymography on Fixed, Paraffin-embedded Tissue: Zinc and Ethanol Fixation Preserve Enzyme Activity
Authors: Hadler-Olsen Elin , Kanapathippillai Premasany , Berg Eli , Svineng Gunbjørg , Winberg Jan-Olof , Uhlin-Hansen Lars
Published: September 2009

In situ zymography is a method for the detection and localization of enzymatic activity in tissue sections. This method is used with frozen sections because routine fixation of tissue in neutral-buffered formalin inhibits enzyme activity. However, frozen sections present with poor tissue morphology, making precise localization of enzymatic activity difficult to determine. Ethanol- and zinc-buffered fixative (ZBF) are known to preserve both morphological and functional properties of the tissue well, but it has not previously been shown that these fixatives preserve enzyme activity. In the present study, we show that in situ zymography can be performed on ethanol- and ZBF-fixed paraffin-embedded tissue. Compared with snap-frozen tissue, ethanol- and ZBF-fixed tissue showed stronger signals and superior morphology, allowing for a much more precise detection of gelatinolytic activity. Gelatinolytic enzymes could also be extracted from both ethanol- and ZBF-fixed tissue. The yield, as analyzed by SDS-PAGE gelatin zymography and Western blotting, was influenced by the composition of the extraction buffer, but was generally lower than that obtained from unfixed tissue.
Chemical State Analysis of Sn and Fe in ZrO2 by Mössbauer Spectroscopy
Authors: Anada H , Takeda K , Nasu S , Kobayashi Y , Nakamichi T
Published: September 2009

Chemical states of Fe and Sn were investigated by Mössbauer spectroscopy using a specially made Zircaloy-4 sheet in which 57Fe and 119Sn isotopes were enriched. Chemical states were compared between these elements in matrix and in oxide corroded in steam at 400°C. As a result, almost all of Fe in Zircaloy-4 matrix precipitated as the intermetallic compounds Zr(Cr0.33,Fe0.67)2. Fe in ZrO2 existed as Fe2+ ions and intermetallic compounds. The amount of Fe2+ in ZrO2 increased with oxidation of Zircaloy-4 during corrosion testing, especially in ZrO2 near the outside surface. Sn dissolved in Zircaloy-4 matrix, and no Zr-Sn intermetallic precipitates were found. Sn exists as Sn2+ and Sn4+ in ZrO2. Correspondence of the alloying element in Zircaloy-4 to corrosion procedure is discussed.
The Cause for Enhanced Corrosion of Zirconium Alloys by Hydrides
Authors: Kim YS , Woo HK , Im KS , Kwun SI
Published: September 2009

The cause of the accelerated corrosion of zirconium alloys by hydrides is studied by investigating the corrosion of three section planes of Zr-2.5Nb tubes with different texture: the longitudinal normal section (LS) plane, the transverse normal section (TS) plane, and the radial normal section (RS) plane. Corrosion tests were conducted on those section planes taken from the unhydrided and prehydrided Zr-2.5Nb tubes with up to 450 ppm H in water at 350°C or in steam at 400°C. For Zr-2.5Nb tube with a strong circumferential texture, the deleterious effect of hydrides on enhanced corrosion was most striking on the LS specimen, while beneficial and little hydride effect on the corrosion was observed on the TS and RS specimens, respectively. However, for Zr-2.5Nb tube with a comparatively radial texture, the deleterious effect of hydrides on enhanced corrosion was observed on all the three section planes. The lattice broadening and the interplanar spacing in the zirconium matrix were measured by using X-rays on those section planes taken from Zr-2.5Nb tubes with a circumferential texture before and after charging with hydrogen. The precipitation of hydrides in the Zr-2.5Nb tube subjected the LS plane to residual tensile stress, expanding the zirconium lattice in the LS, and the TS plane to compressive stress, contracting it in the TS. Based on these results, the corrosion acceleration by hydrides is discussed by correlating the change in the zirconium lattice distance or lattice distortion including residual stress and the corrosion on each plane before and after charging with hydrogen. This finding leads us to the conclusion that the major controlling factor to the corrosion of zirconium alloys is the lattice coherency between the metal and the oxide.
Effects of Neutron Irradiation on the Microstructure of Alpha-Annealed Zircaloy-4
Authors: Bajaj R , Kammenzind BF , Farkas DM
Published: September 2009

Analytical electron microscopy (AEM) was used to study the separate effects of the irradiation parameters on the evolution of the microstructure in recrystallized alpha-annealed Zircaloy-4 under controlled irradiation conditions. The effects of fast neutron flux from ∼4 × 1013 n/cm2-s to ∼1.5 × 1014 n/cm2-s (E > 1 MeV)3 neutron fluence in the range of ∼15 × 1020 n/cm2 to ∼50 × 1020 n/cm2 and temperature from ∼270 to ∼330°C were studied. The completeness of the test matrix and the exposure in the controlled environment of the advanced test reactor permitted the separate effects of fast neutron flux, fluence, and irradiation temperature to be delineated for the first time. It was found that an increase in the neutron flux increases the degree of amorphization of the second-phase precipitates but retards the redistribution of iron out of the amorphous region (neutron fluence and irradiation temperature remaining the same), whereas increasing temperature (neutron flux and neutron fluence remaining the same) has a reverse effect. Overall, the rate of amorphization of the second-phase precipitates observed in this work was larger than that predicted by many existing literature models. Finally, neither segregation of alloying elements to grain boundaries nor precipitation of any new phases were encountered.
Quantitative Assessment of Irradiation Effect on Creep and Corrosion Properties of Zr-Base Alloys
Authors: Kido T , Senda Y , Tukuta Y , Hayashi H , Murai K
Published: September 2009

In order to qualify the properties of alternative zirconium-base alloys as fuel cladding material in PWRs, the segmented fuel rod irradiation program is being performed. In this program, segmented fuel rods were irradiated in Vandellos-2 to have burn-ups of 25 to 60 GWd/t, and more than 40 rods were examined by profilometry and/or eddy-current oxide measurement in hot cells at Studsvik. In parallel to the irradiation test, out-of-pile creep and corrosion tests were carried out on the archive claddings.

One segmented fuel rod consists of seven segments axially connected, and it therefore has a unique feature, existence of plenums in the middle of the fuel stack region (in-flux plenum). Since evaluation of the temperature at plenums during operation is easier than at fuel regions, direct comparisons of the creep and corrosion behaviors with and without irradiation were able to be done.

The irradiation effect on the corrosion properties were determined to accelerate the corrosion rate by a factor of 2 to 3 as increasing exposure time in the reactor irrespective of the cladding variants. On the other hand, evaluations of the creep-down behavior at plenums have shown that niobium-bearing zirconium alloys (MDA: 0.8Sn-0.2Fe-0.1Cr-0.5Nb, ZIRLO™: 1Sn-0.1Fe-1Nb) had an irradiation creep rate of 1/2 to 2/3 compared to that of Zircaloy-4, whereas conventional tin and low tin Zircaloy-4s showed little difference. This restraining effect of niobium is comparable to the influence of niobium on the axial length change of the rods.
Zirconium in the Nuclear Industry: Thirteenth International Symposium
Authors: Moan GD , Rudling P
Published: September 2009

Description

This unique publication provides an international overview on the production and use of Zr alloys, their properties and behavior during nuclear service, the design of Zr components and their testing after service. Papers cover the historical aspects of research on Zr alloys; basic metallurgy, including studies of second phase particles; irradiation creep and growth; material performance during LOCA (loss of coolant accidents); and RIA (reactivity initiated accident).

Half of the papers in STP 1423 relate to corrosion and hydriding behavior, the most important current issues in the industry. A quarter of the papers deal with in-reactor studies. The remaining papers discussed the behavior and properties of Zr alloys for the intermediate storage of spent fuel.

STP 1423 is a valuable resource for engineers and scientists involved in the processing and properties of Zr alloys, the production and use of Zr alloy reactor components, their behavior during service and property changes that occur with increasing neutron fluences.

42 peer-reviewed papers provide an international overview of the production and use of Zr alloys.

Learn about:

• Production and use of Zr alloys in the nuclear industry

• Properties and behavior during nuclear service

• Corrosion and hydriding during service

• Dimensional changes during service

• Design of Zr components

• Testing after service

• Effect of alloy microstructure and composition on behavior

• Studies of the composition, properties and behavior of the oxides formed during service
Fatigue and Fracture Mechanics: 35th Volume
Authors: Link Richard E. , Nikbin Kamran M.
Published: September 2009

Description

Thirty-eight peer-reviewed papers cover the latest research on fracture mechanics, including fracture, fatigue, residual stress, creep, creep/fatigue, constraint and stress corrosion and links them to concepts used in structural integrity assessment. Furthermore this publication does not restrict itself to metallic materials but is applicable to polymers, composites as well as inhomogeneous materials. These papers, written by nationally and internationally recognized authors, cover the general areas of modeling, testing, and validation in crack dominant related research.

Other topics cover experimental results coupled to modeling techniques of linear, non-linear, time independent and dependant behavior of cracked geometries of a range of materials. Papers relating to residual stress, crack tip constraint and probabilistic methods of analyses also highlight the importance of developing these fields for future improvements in life assessment methods.
Symposium on Non-Destructive Testing Introduction
Authors: Wenk SA
Published: September 2009

Committee E-7 on Non-Destructive Testing of the American Society for Testing Materials firmly believes that one of its duties to its membership is the presentation of advanced non-destructive testing methods and techniques in use throughout the world.
Microstructure of Age-Hardenable Alloys
Authors: Mihalisin JR , Carroll KG
Published: September 2009

The age-hardening phase in the most common nickel-chromium alloys hardened with aluminum and titanium is based on the ordered compound N13AI, which is usually denoted in phase diagrams as the gamma prime (γ) phase (1). In alloys of this type, it is generally thought that titanium as well as chromium, iron, and perhaps other elements can enter the gamma prime phase substitutionally. This latter circumstance provides an explanation for the fact that the volume of γ precipitate observed in these alloys is far beyond what one would expect if only pure Ni 3Al formed. Recently the importance of grain boundary carbide phases upon properties in these systems has also been recognized (2).
The Application of Electron Diffraction and Electron Microscopy in Studies of Minor Phases of Heat-Resistant Alloys
Authors: Bigelow WC , Brockway L , Freeman JW
Published: September 2009

The method of Heidenreich, combining electron diffraction and electron microscopic examinations of etched surfaces for identifying and studying the distribution of minor phases of metal systems, has been applied to heat-resistant alloys. General considerations in preparation of surfaces of these alloys for electron metallographic examination are discussed. Applications of the method to four typical alloys, 16-25-6, Inconel-X, S816, and N-155, are described. Two different minor phases, M23C6 and M6C, were identified in the 16-25-6 alloy, and four phases, TiN, CbN, M23C6, and γ, were identified in Inconel-X. In both of these alloys, the phases present were found to vary for different aging treatments, and correlations between the precipitation processes and some metallurgical properties were possible.
Subcommittee VII (Accelerated Tests for Protective Coatings)
Authors: Sawyer Roscoe H.
Published: September 2009

Interest in accelerated tests in Committee D-1 dates back to about 1910 when Committee D-1 was set up as the successor to Committee E. The report of Committee D-1 for 1910 shows a Subcommittee (H) on Accelerated Tests.
Subcommittee XII (Exterior Exposure Testing on Wood)
Authors: Vannoy W. G.
Published: September 2009

Subcommittee XII was organized in 1947 to develop or assemble methods for conducting exterior exposure tests of paints on wood, from procedures then current. It took 4 years to accomplish this. Wayne R. Fuller, Grand Rapids Varnish Co., was responsible for organizing and guiding the activities of the committee.
Subcommittee XVI (Printing Inks)
Authors: Zettlemoyer A. C.
Published: September 2009

Work on printing inks under the auspices of the ASTM was initiated in 1949 by the organization of a D-1 Subcommittee with the understanding that it might be established as a separate Technical Committee at the opportune time.
Subcommittee XVIII (Physical Properties of Materials)
Authors: Euvekard Maynard R.
Published: September 2009

In 1916; a special group was appointed to advise Committee D-1 on the practicability of a coordinated study of the physical problems connected with paint. The ASTM Year Book of 1917 listed F. P. Ingalls (chairman), H. A. Gardner, M. Y. Seaton, and G. W. Thompson as members of Subcommittee XVIII.
Tear Tests for Fluid-Applied Roofing Membranes at Joint in Roof Deck
Authors: Koike Michio
Published: September 2009

Four kinds of fluid-applied roofing membranes were tested by three different methods for the purpose of evaluating the ability to withstand movements which took place in roof decks. All of them could not withstand the movements from 0 to 1.0 mm; then it is advisable, at the present time, to apply these membranes to the roofs where movements as small as 0.5 mm are expected to take place. The test methods adopted in this paper are only tentative ones. The ability to withstand the movements in the roof deck is so important for the roofing membranes that establishment of standard test methods is an urgent necessity for improvement of roofing membranes.
Wind-Uplift Resistance of Built-Up Roofs
Authors: Donegan J. W. , Butterfield W. L.
Published: September 2009

Wind-uplift resistance of nailed-construction built-up roofs is a function of the withdrawal strength of the fastener and the pull-through resistance of the base sheet. As a means for facilitating evaluation of base sheets, a nail pull-through test applicable to saturated felts and coated base sheets has been developed.
Study of Vacuum Carbon-Deoxidization of High Carbon Chromium Bearing Steel
Authors: Zheng Li , Minghua Xu
Published: September 2009

This paper describes the negative influence of high residual aluminum which is used as a deoxidant in the steel and raises the newest control requirement for high carbon steel on residual aluminum. By means of thermodynamic calculation and production practices, the total oxygen (∑[O]) in the steel can be 10 ppm through carbon-oxygen reaction under the conditions of high vacuum, proper top slag composition, and argon stirring during ladle refining/vacuum degassing (LF/VD) processes of high carbon chromium bearing steel. Meanwhile, the size of D-type inclusion in the steel is obviously reduced. Thus, the purity of the bearing steel is improved. Since the consumption of aluminum used for deoxidation is reduced, the unit cost of bearing steel is obviously reduced.
A Statistical Method to Assess the Reliability of Cleanness Measurements for High Quality Bearing Steels
Authors: Hénault Eric
Published: September 2009

During the past decade, greatly increased in-service demands on finished products such as gears, bearings, and springs have inspired a wish by steel makers to guarantee the highest level of cleanness in their steels. In order to achieve this, it has been necessary to develop methods of characterization of cleanness which can describe all the nonmetallic inclusion populations endogenous and exogenous contained in the steel. These methods are essentially based on quantitative metallography and ultrasonic tests. Statistical tools have also been developed to maximize the accuracy of measurements in relation to the time taken to make them, and to answer the key question: What is the minimum analyzed volume for which a measurement can be expected to yield a reliable estimate of a specific in-service property? For quantitative metallographic methods, smaller inclusion densities necessitate an increase in the surface area analyzed, and the study of a larger surface is time consuming. Extreme value analysis is a further method for prediction of the expected size of the largest inclusion in a volume. Often, however, the amount of material examined is not sufficient to assess the quality of the heat with complete certainty. Other tools that have been developed utilize high frequency ultrasonic tests over a frequency range from 10 to 100 MHz, which make it possible to detect inclusions with diameters ranging from 15 μm to 1 mm. In all cases, in order to obtain accurate estimates of the densities of nonmetallic inclusions, it is important to know the appropriate settings for the measurement method. In particular, it is very important to estimate the diagnosis error when we rate a product on the basis of measurements. For each of these inspection techniques, statistical models have been developed to assess the main statistical properties of the methods. The results are reported here. They give a basis for comparison of steel heats that takes account of knowledge of the confidence level of the various measurement methods.
Developing ASTM E 2283: Standard Practice for Extreme Value Analysis of Nonmetallic Inclusions in Steel and Other Microstructural Features
Authors: Hetzner Dennis W.
Published: September 2009

The statistical nature of bearing failures has been studied using Weibull probability statistics for over 50 years. Historically it has been demonstrated that the origin of many bearing failures is the presence of large nondeformable nonmetallic inclusions in the bearing steel. Methods for predicting the presence of large inclusions in bearing steels using extreme value statistics were presented in the late 1980s. Several papers presented in the ASTM A 01.28 Bearing Steel Technology Symposium in 1996 discussed this method of analysis. Unfortunately in these and other investigations, standardized methodologies for performing the analysis were not utilized. This paper discusses how ASTM E 2283 was developed. The results of a recently completed interlaboratory round robin testing program are discussed. The application of the standard to microstructural features other than inclusions will be illustrated.
Statistical Analysis of Nonmetallic Inclusions for the Estimation of Rolling Contact Fatigue Range and Quality Control of Bearing Steel
Authors: Girodin Daniel , Dudragne Gilles , Courbon Joel , Vincent Alain
Published: September 2009

The cleanliness of bearing steels is a critical factor that influences directly the rolling contact fatigue performance and other mechanical properties of bearings. Hence, the evaluation of nonmetallic inclusions is a very important issue for steelmakers, bearing producers, and users. The material qualification procedure includes classical inclusion rating and rolling contact fatigue tests as acceptance tests for evaluating steel suppliers and ensuring the required bearing performance. The evolution of steel cleanliness had led to an increase in fatigue life so that running time of rolling contact fatigue tests have been considerably extended, until they became too time and cost consuming for a realistic qualification. In this paper, quantitative metallographic evaluation of the inclusion cleanliness used to collect data on the size, type, and expected number of inclusions in small samples is presented. The data were analyzed using Statistics of Extreme Values (SEV) and the results were used to extrapolate in larger samples representative of actual volumes of material involved in rolling contact fatigue tests and were related to the fatigue life of bearing steels from different suppliers. This method gives useful and reliable statistical data on inclusions for evaluating the performance level under rolling contact fatigue and defines the required cleanliness characteristics for bearing steels qualification. Other information of this work is the ability of the statistical inclusion rating to serve as a substitute for rolling contact fatigue tests to forecast the performance level of bearing steels.
Cleanliness of Bearing Steels and Fatigue Life of Rolling Contacts
Authors: Kerrigan A. , Kuijpers J. C. , Gabelli A. , Ioannides E.
Published: September 2009

Established metallographic methods of determining the cleanliness of bearing steels with respect to micro-inclusions, such as ASTM E 45, are capable of differentiating poor quality melts from good quality melts. However, as steelmaker capabilities improve, with increasing numbers being able to consistently produce good quality melts, the established methods of cleanliness assessment are unable to differentiate between melts. These established methods, which give single figure ratings based on both the size and number of inclusions, are extremely difficult to use in predicting the performance of a bearing component under conditions of rolling contact fatigue. In this work, the method of Extreme Value Analysis (EVA) is used to characterize the inclusion population of five different steel melts of known and varying quality. A link between the EVA distribution and the measured bearing life, performed on material with a low reduction ratio, is also presented.
Influence of Steel Making and Further Processing on the Distortion of Bearing Steel Components
Authors: Volkmuth Johann
Published: September 2009

Distortion of bearing steel components after hardening has a major influence on the total manufacturing cost of bearings. This publication presents results and experiences of recent investigations regarding possible causes for the distortion of bearing rings. It does not consider the influence of the soft machining and of the hardening process itself but concentrates on the contribution of the steel grade as such, the casting conditions, and the further processing. Based on a systematic approach, it will be shown how such parameters influence both the dimensional variations (like ovality or conicity of the rings) and the dimensional changes (such as mean diameter) after the hardening operation. Such results can help to minimize distortion by selection of suitable steel making and further processing routes and, thus, to reduce manufacturing cost of bearing steel rings.
A Novel Method to Evaluate the Influence of Hydrogen on Fatigue Properties of High Strength Steels
Authors: Matsubara Yukio , Hamada Hiroshi
Published: September 2009

In rolling contact fatigue, hydrogen is believed to contribute to early flaking failures under some conditions. Hydrogen diffuses quickly in steels, even at room temperature, thus resulting in its dissipation into the surrounding atmosphere. This condition presents a uniquely difficult challenge for evaluating the intrinsic fatigue properties related to hydrogen embrittlement. In order to compensate for this, we employed ultrasonic fatigue testing at a loading frequency of 20 kHz, because a high loading frequency offsets the rapid hydrogen loss. In this report, the fatigue properties of hydrogen pre-charged JIS-SUJ2 (SAE52100 equivalent) were assessed. The amount of hydrogen was quantitatively measured by thermal desorption analysis. The diffusion coefficient of hydrogen was determined via electrochemical hydrogen permeation testing. These results indicate that the magnitude of fatigue strength reduction is directly proportional to the diffusible hydrogen content. Included with this report is our proposed method for evaluating fatigue strength related to hydrogen embrittlement.
Comparison of Fatigue Performances of 32CrMoV13 and M50 Steels in Presence of Surface Indents
Authors: Vincent Alain , Nelias Daniel , Jacq Christophe , Robin Yohann , Dudragne Gilles
Published: September 2009

The fatigue resistance of 32CrMoV13 nitrided steel in the presence of controlled surface indents is investigated in comparison with M50 reference steel. For that purpose, rolling contact fatigue tests have been performed on a two-disk machine under pure rolling and rolling plus sliding conditions. Artificial indents are produced by using a hardness machine equipped with spherical diamond tips of different radii. The overall set of data shows better performances for 32CrMoV13 nitrided steel. The specific properties of this steel are highlighted by microstructural observations. The results are discussed in terms of endurance limit in presence of indents. The hierarchy of theoretical harmfulness thus obtained for the various indents tested in this work agrees well with that observed experimentally.
Characterization of Wear and Surface Reaction Layer Formation on Aerospace Bearing Steel M50 and a Nitrogen-Alloyed Stainless Steel
Authors: Peissl Sven , Leitner Harald , Ebner Reinhold , Hutter Herbert , Krecar Dragan , Rabitsch Roland
Published: September 2009

The formation of reaction layers on surfaces in mechanical contact is strongly affected by the tribological loading conditions, the materials used, the lubricant and the service temperature. An appropriate balance between reactivity of material and lubricant in tribological systems decreases wear and friction and increases the durability. The goal of this paper is to compare the reaction layer formation on a standard aerospace bearing steel AMS 6491 (M50) with that on a high strength stainless steel grade AMS 5698 exhibiting a nominal chemical compositions of 0.82C-4.1Cr-1V-4.2Mo (wt. %) and 0.3C-0.4N–15.2Cr-1Mo (wt. %), respectively. As lubricant jet engine oil Mobil Jet II has been used. Rolling contact fatigue (contact pressure: 6 GPa) and ball-on-disk tests (contact pressure: 1.6 GPa, sliding speed 10 cm/s) at room temperature and at 150°C were employed to study the effect of extreme loading conditions and temperature dependence of the reaction layer formation. The contact areas were inspected by means of optical profilometry, scanning electron microscopy (SEM), and secondary ion mass spectrometry (SIMS) in order to determine type, thickness, homogeneity, and distribution of the reaction layers in the contact zone. The main result of the study is that the reaction layer formation is significantly less on the stainless steel grade compared with M50. SIMS depth profiles were determined in order to explain the differences in the wear characteristics of the two materials. The reaction layers are mainly built up of PXOY molecules, which might be phosphates resulting from the tricresyl phosphate (TCP) lubricant additive. The role of the chemical reaction of the steel and TCP regarding the layer formation will be discussed.
Micro-Plastic Material Model and Residual Fields in Rolling Contacts
Authors: Popescu Gabriel , Gabelli Antonio , Espejel Guillermo Morales , Wemekamp Benny
Published: September 2009

This paper describes a model for the prediction of micro-plastic material transformation and associated residual stress field development in bearing steels during over-rolling. The high and mainly hydrostatic pressure field induced by the rolling element load, leads to the development of micro-plastic deformation in the subsurface layer of the rolling contact. The resulting plastic strain distribution gives rise to an associated self-equilibrating residual stress field that can be experimentally quantified using X-ray diffraction methods. A novel three-dimensional elastic-plastic over-rolling solution is used to evaluate the plastic strains and material transformation. Central to this plastic contact formulation is the incremental approach to deal with nonlinear material behavior. The Prandtl-Reuss constitutive equations in conjunction with Huber-Mises-Hencky yield criterion and Ramberg-Osgood strain-hardening relationships are applied to describe the plastic behavior of common hardened bearing steels. A nonlinear isotropic law is applied to describe the transformation of the retained austenite during stress cycles and changes in the strain-hardening behavior of the material microstructure. Application of this model with an incremental solution scheme based on the Conjugate Gradient Method (CGM) gives good convergence properties and fast solution for each cycle. Comparison between experimentally obtained residual stresses and stress fields derived from the present micro-plastic contact model, indicates good agreement. Numerical simulations, carried out to derive the maximum operating contact pressures in the elastic regime are also in agreement with published data. The model opens new possibilities in the evaluation of steels and heat treatments used in rolling bearings. Furthermore, this micro-plastic contact model may help the interpretation of the load history leading to a given pattern of residual stress measured in bearing rings.
Testing of Building Mortars Using the New British Standard Methods
Authors: Gillard R. , Lee H. N.
Published: September 2009

The proposal of the British Standard for mortars is that all ingredients of mortars should be specified by weight proportions of the total dry weight of the mortar. In the case of lime:sand mortars it also is suggested that the “available lime content,” as specified by ASTM Method C 25-65, is used to determine the active lime in the mortar.

In the first part of this investigation the effects of varying the available lime content on the physical properties of mortars have been studied. It has been shown that using one sand and one hydrated lime the physical properties of the plastic mortars are related to the available lime content, and that when hydrated lime mortars are aged for 24 h as a mortar the test methods are more reproducible.

In the second part of this investigation a number of different types of limes have been tested in the form of lime:sand mortars and gaged with portland cement. From the results of the second series of tests it was shown that controlling the amount of lime in a mortar by its available lime content is a useful form of standardization, but that the physical properties of different types of lime do affect the final properties of the mortar.

The proposed British Standard methods of testing mortars were found to give reasonably satisfactory results and capable of classifying types of building mortars.
Effects of Calcination Conditions on the Properties of Lime
Authors: Mullins R. C. , Hatfield J. D.
Published: September 2009

Experiments were made to define quantitatively the effects and interactions of the time of calcination, the temperature of calcination, and the particle size of a pure limestone upon the properties of the calcine that may affect the absorption of sulfur dioxide from flue gases. Response surfaces were derived for the degree of calcination, pore volume, density, crystallite size, and capacity to absorb sulfur dioxide as functions of the calcination conditions. It is predicted that wide variation in the degree of utilization will occur over relatively narrow ranges of retention time and injection temperature likely to be encountered in attempts to control sulfur dioxide emissions by injecting limestone in power plant furnaces.
Observations on the Solution of Calcium Oxide in Slag Systems
Authors: Derge Gerhard , Shegog J. R.
Published: September 2009

A modified hot-filament microscope is used for direct observation of the solution of calcium oxide (CaO) in synthetic melts simulating slags of metallurgical interest.

In the CaO-SiO2 system the process is uncomplicated in acid slags. However, in basic slags, when the composition approaches the liquidus in equilibrium with 2CaO•SiO2, a protective film develops which has many of the characteristics of a glassy phase. The crystallized film has the composition of 2CaO•SiO2, and crystallization results in more rapid solution of the CaO, apparently on account of the associated decrease in specific volume.

This mechanism operates with or without imposed temperature gradients and convection. It is not changed significantly by small additions of other common slag components. It appears to be general and has been observed in all other binary systems studied, including MgO-SiO2 and CaO with Al2O3, P2O5, B2O3, and V2O5. Related experiments have demonstrated the release of oxygen gas as a result of the combined influence of temperature and composition gradients during CaO solution. This is due to the change in the ferrous/ferric ion ratio and associated changes in slag structure.

Presentation based on high-temperature micrographs.
Characterization of Lime: A Comparison and Scaling Down of the Coarse Grain Titration Test and the ASTM Slaking Rate Test
Authors: Schlitt W. J. , Healy G. W.
Published: September 2009

A comparison of the ASTM slaking rate test and the German coarse grain titration test was made using results obtained from trials on hard-, medium-, and soft-burned lime. Included in the comparison were such factors as the relative slaking rate, the thermal behavior, and the effect of variations in the prescribed test procedures. Both methods proved to be reproducible and were generally suitable for industrial use. However, the German test required less time for hard-burned lime and covered a wider range of properties within its specifications. From the comparison a correlation was worked out which allowed the results of one test to be translated into those of the other test. A scaled-down version of the titration test also was developed which duplicated the results of the full-scale test.
Crucible Test for Lime Reactivity in Slags
Authors: Limes R. W. , Russell R. O.
Published: September 2009

The rapid acceptance of basic oxygen furnace (BOF) steelmaking has caused a veritable revolution within the steel industry and also the lime industry as a major supplier of a raw material. The speed of the process requires a lime product which goes into solution rapidly to form a slag. Field observations of the BOF steelmaking process showed major differences in the rate of slag formation with various commercial lime products. Operating practices could be adjusted to take poor lime into solution but would have a detrimental effect on the furnace refractories and metallurgical processing. The slagmaking reactions are discussed.

The ASTM water reactivity test for lime would differentiate between the lime products observed to react differently in BOF slagmaking. However, arguments were made that this test did not simulate slagmaking or lime solution rate in a slag. A crucible test was devised in which minus 5 plus 6 mesh lime sample is mixed with a lime deficient slag and heated for various lengths of time. The free lime is determined in the fired samples and plotted against time. This gives an indication of solution rate. A correlation was found between this crucible test and the ASTM water reactivity test for commercial lime products of interest. There are ways to lower water reactivity without decreasing slag solution rate, notably through prereaction with other slagmaking ingredients. The crucible test has been used to evaluate these experimental products.

The water reactivity test is adapted more easily to plant quality control than is the crucible test. Since the correlation existed between the two for products of interest, the water reactivity test was selected for control of incoming lime product. Specifications were established for reactivity, loss on ignition, sulfur, and calcium oxide content. The specifications are realistic and can be met by commericial suppliers of lime.