bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effects of a Hypertext Learning Aid and Cognitive Style on Performance in Advanced Financial Accounting
Authors: Jones Stuart H. , Wright Michael E.
Published: February 2010

ABSTRACT: This study extends previous work by combining the effect of cognitive style and the use or non-use of two versions of a hypertext learning aid and their interaction on student performance in advanced financial accounting. One-third of the students did not use a learning aid at all, one-third used a basic version of the learning aid (where only the solution was provided), and one-third used an extended version of the learning aid (where both the solution and derivation of the solution is provided). An additional extension of the prior literature is that these effects were investigated on two different kinds of examination questions. The results demonstrate that for a familiar exam question, only the learning aid was significant, and for an unfamiliar exam question, the learning aid, cognitive style, and the interaction between learning aid and cognitive style were significant. For both types of questions, performance differed based upon cognitive style. These results suggest that educators should be careful when designing and using learning aids.
Snowy Ridge Ski Resort: Fair Value Measurement and the Impairment of Long-Term Assets
Authors: Gore Richard A. , Herz Paul J.
Published: February 2010

ABSTRACT: The Snowy Ridge Ski Resort case study illustrates the use the new Fair Value Measurement Standard (SFAS No. 157) with various assets in connection with the acquisition of a ski resort and subsequent test for impairment. The case study introduces students to the two primary approaches for measuring fair value (Market and Income). These approaches are then used to compute fair value for a variety of assets. In addition, students become familiar with the Fair Value Hierarchy and classify fair value measures in accordance with the hierarchy. The assets to which the fair value measures are generated include: marketable securities; property, plant, and equipment; real estate under development; and goodwill. The fair values and other input data are then used to test for impairment of the operating assets and goodwill. Thus, the case study illustrates the interplay between fair value measurement and impairment testing in a simple setting to give the student a foundation for understanding how fair value measurement is used in GAAP for operating assets.
Interactive Financial Reporting: An Introduction to eXtensible Business Reporting Language (XBRL)
Authors: Taylor Eileen Z. , Dzuranin Ann C.
Published: February 2010

ABSTRACT: As technology provides more efficient and effective methods for financial reporting, students are encouraged to gain experience using these innovations. The SEC and other global financial communities have mandated the use of XBRL (eXtensible Business Reporting Language) for certain public filings. The following interactive exercise exposes students to XBRL and provides hands-on experience in using related tools. In Task 1, students learn about the underlying mechanics of XBRL. In Task 2, students use a programmed learning approach to analyze financial information using the SEC’s free interactive financial viewer. Task 3 includes discussion questions related to XBRL and specific accounting courses (i.e., financial, audit, managerial, and systems).
A Profile of Inpatient Admissions to an Aged Psychiatry Service in Victoria
Authors: Smith Brad , Hassett Anne , Harrigan Susan , Fortune Tracy
Published: February 2010

Objective: The study aimed to characterize the demographics, diagnostic makeup and aspects of patient management for the inpatient population of a large aged psychiatry service.

Method: Sociodemographic and clinical variables were retrospectively collated from inpatient files and discharge summaries over a 3-year period. Age, gender, country of birth, diagnostic group, length of stay, involuntary care status and number of admissions were described and analysed. A total of 604 patients were included in the study, with complete data available for 516.

Results: Approximately half of the patients were aged 65–75 years and 59.3% were female. More than half had been born outside of Australia. The primary diagnosis was an affective disorder in 39.0% of admissions, dementia in 27.5% and psychotic illnesses in 25.8%. The median length of stay was 28 days; 60.8% had a period of involuntary care and 79.8% had only one admission.

Conclusion: In the near future, aged psychiatry services will face increased numbers of patients and rising expectations. To best respond to these challenges, we need to have an understanding of current patient and service profiles. The findings of this study illustrate a range of patient, diagnostic and management variables in aged psychiatry practice. This information can be used for comparison with other services and in planning for future development of services.
Dr Google, MD: A Survey of Mental Health-Related Internet Use in a Private Practice Sample
Authors: Lam-Po-Tang John , McKay Diana
Published: February 2010

Objective: The aim of this study was to evaluate the use of the internet to access mental health-related information in a private practice sample, and to understand how this influenced health behaviours in this group.

Method: We undertook a cross-sectional survey of adult outpatients attending two group psychiatric practices. The content included internet usage, types of information located, disclosure with treating psychiatrist, and perceived influence on decision-making. We collected both quantitative and qualitative data.

Results: The internet was often used to access mental health-related information. Respondents most commonly looked for information about symptoms, treatment, side effects and diagnoses. Approximately one-third of those who sought mental health information on the internet discussed this with their psychiatrist, and those who did so were more likely to report an influence of this information on their decision-making. Respondents' comments suggested an appreciation of the utility of the internet, combined with an understanding of its limitations

Conclusion: Private practice patients frequently access mental health information from the internet. When discussed within the therapeutic setting, it appears more likely to influence health-related decision-making. As part of ongoing therapy, clinicians should actively discuss what patients have read on the internet.
Severe Laryngeal Dystonia in a Patient Receiving Zuclopenthixol “Acuphase” and Fluoxetine
Authors: Hood Sean , Orr Kenneth , Bennett Lynette , Davies Simon
Published: February 2010

Objective: Prescribers are warned to be vigilant for potential cytochrome P450 mediated drug interactions; guidelines separately highlight risks of toxicity associated with zuclopenthixol acuphase. We previously examined potential cytochrome P450 interactions with zuclopenthixol and here describe dangerous side effects in a patient receiving zuclopenthixol acuphase and the selective serotonin reuptake inhibitor fluoxetine at high dose.

Method: We present the case of a patient established on fluoxetine 80 mg/day who subsequently received injected zuclopenthixol acuphase 100 mg.

Results: Following zuclopenthixol acuphase administration, dangerous extra-pyramidal side effects were observed, including severe laryngeal dystonia necessitating emergency medical treatment.

Conclusions: Our observations of symptoms of zuclopenthixol toxicity are consistent with a cytochrome P450 2D6/3A4 interaction with fluoxetine. Previous evidence demonstrating this interaction included only patients taking fluoxetine up to 60 mg/day. This case extends the evidence base. In patients taking high dose fluoxetine, we advise marked reductions in the prescribed dose of zuclopenthixol acuphase.
Efficiency Evaluation of Autonomic Heart Control by Using the Principal Component Analysis of ECG P-Wave
Authors: Simoliuniene R. , Tamosiunas M. , Saferis V. , Vainoras A. , Gargasas L. , Krisciukaitis A.
Published: February 2010

Background: Cardiac output is controlled by the autonomic nervous system by changing the heart rate and/or the contractions of the heart muscle in response to the hemodynamic needs of the whole body. Malfunction of these mechanisms causes the postural orthostatic tachycardia syndrome and/or the chronic fatigue syndrome. Evaluation of functionality and efficiency of the control mechanisms could give valuable diagnostic information in the early stages of dysfunction of the heart control systems and help to monitor the healing process in rehabilitation period after interventions.

Objectives: In this study we demonstrate how P-wave changes evoked by an ortho-static test could be quantitatively evaluated by using the method based on the principal component analysis.

Methods: ECG signals were recorded during an orthostatic test performed according to the typical protocol in three groups of volunteer subjects representing healthy young and older persons, part of which had transient periods of supraventricular arrhythmias. Quantitative evaluation of P-wave morphology changes was performed by means of principal component analysis-based method.

Results: Principal component-based estimates showed certain variety of P-wave shape during orthostatic test, what revealed a possibility to evaluate the properties of para-sympathetic heart control.

Conclusions: Quantitative evaluation of ECG P-wave changes evoked by an orthostatic test by using a newly developed method provides a quantitative estimate for functionality and efficiency of the heart rate control mechanisms. The method could be used in eHealth systems.
Convergent syntheses of LeX analogues
Authors: Wang An , Hendel Jenifer , Auzanneau France-Isabelle
Published: February 2010

The synthesis of three Lex derivatives from one common protected trisaccharide is reported. These analogues will be used respectively for competitive binding experiments, conjugation to carrier proteins and immobilization on gold. An N-acetylglucosamine monosaccharide acceptor was first glycosylated at O-4 with a galactosyl imidate. This coupling was performed at 40 °C under excess of BF3·OEt2 activation and proceeded best if the acceptor carried a 6-chlorohexyl rather than a 6-azidohexyl aglycon. The 6-chlorohexyl disaccharide was then converted to an acceptor and submitted to fucosylation yielding the corresponding protected 6-chlorohexyl Lex trisaccharide. This protected trisaccharide was used as a precursor to the 6-azidohexyl, 6-acetylthiohexyl and 6-benzylthiohexyl trisaccharide analogues which were obtained in excellent yields (70–95%). In turn, we describe the deprotection of these intermediates in one single step using dissolving metal conditions. Under these conditions, the 6-chlorohexyl and 6-azidohexyl intermediates led respectively to the n-hexyl and 6-aminohexyl trisaccharide targets. Unexpectedly, the 6-acetylthiohexyl analogue underwent desulfurization and gave the n-hexyl glycoside product, whereas the 6-benzylthiohexyl analogue gave the desired disulfide trisaccharide dimer. This study constitutes a particularly efficient and convergent preparation of these three Lex analogues.
Chemical synthesis using enzymatically generated building units for construction of the human milk pentasaccharides sialyllacto-N-tetraose and sialyllacto-N-neotetraose epimer
Authors: Schmidt Dirk , Thiem Joachim
Published: February 2010

α,2-3- and α,2-6-sialylated lactosaminide precursor structures obtained by various enzymatic procedures could be used for glycosylations employing triflic acid/N-iodosuccinimide. Easily accessible selectively protected lactoside derivatives served as acceptor disaccharides to give the corresponding human milk pentasaccharides in good yields. These were characterized by spectroscopic means in the form of their peracetylated derivatives.
Benzyne arylation of oxathiane glycosyl donors
Authors: Fascione Martin A , Turnbull W Bruce
Published: February 2010

The arylation of bicyclic oxathiane glycosyl donors has been achieved using benzyne generated in situ from 1-aminobenzotriazole (1-ABT) and lead tetraacetate. Following sulfur arylation, glycosylation of acetate ions proceeded with high levels of stereoselectivity to afford α-glycosyl acetates in a ‘one-pot’ reaction, even in the presence of alternative acceptor alcohols.
(Pseudo)amide-linked oligosaccharide mimetics: molecular recognition and supramolecular properties
Authors: Jiménez Blanco José L , Ortega-Caballero Fernando , Ortiz Mellet Carmen , García Fernández José M
Published: February 2010

Oligosaccharides are currently recognised as having functions that influence the entire spectrum of cell activities. However, a distinct disadvantage of naturally occurring oligosaccharides is their metabolic instability in biological systems. Therefore, much effort has been spent in the past two decades on the development of feasible routes to carbohydrate mimetics which can compete with their O-glycosidic counterparts in cell surface adhesion, inhibit carbohydrate processing enzymes, and interfere in the biosynthesis of specific cell surface carbohydrates. Such oligosaccharide mimetics are potential therapeutic agents against HIV and other infections, against cancer, diabetes and other metabolic diseases. An efficient strategy to access this type of compounds is the replacement of the glycosidic linkage by amide or pseudoamide functions such as thiourea, urea and guanidine. In this review we summarise the advances over the last decade in the synthesis of oligosaccharide mimetics that possess amide and pseudoamide linkages, as well as studies focussing on their supramolecular and recognition properties.
Chemical Properties, Microbiological Quality and Sensory Evaluation of Chicken and Duck Liver Paste (foie gras)
Authors: Abu-Salem Ferial M. , Abou Arab Esmat A.
Published: February 2010

Liver paste or foie gras, which is a French term meaning “fatty liver”, was produced traditionally from goose and duck. Chickens are also used in the making of foie gras. The present study deals with the properties and quality of raw chicken and duck liver in comparison with manufactured liver paste (foie gras). Raw chicken liver contained 24.60% protein, 6.00% fat, 1.40 % ash, and 66.80% moisture. The average mineral values were 83.65, 50.75, 5.29, 1.15, 0.154, 0.683, 0.317 and 0.066 μg/g of Fe, Zn, Cu, Mn, Cd, Pb, Ni, and Cr, respectively. The processing of liver paste (Foie gras) changed the composition of raw liver due to a loss in moisture, a release of fat and the addition of butter as a fat source. Chicken liver paste contained 27.8% moisture, 10.1% protein, 58.2% fat, and 0.8% ash. Mineral contents were 68.90, 40.50, 1.60, 1.1, 0.08, 0.22, 0.04 and 0.04 μg/g of Fe, Zn, Cu, Mn, Cd, Pb, Ni, and Cr, respectively. The chemical, microbiological and sensory evaluation of liver paste (foie gras) manufactured from raw liver and preserved by the addition of 1000 ppm of both benzoic acid (BA) or sorbic acid (SA) and a mixture of 500 ppm of both BA plus SA with or without pasteurization at 85 °C were studied during the storage period for 9 days at 4 °C. Presumably, the mixing of liver paste (Foie gras) from chicken liver with 500 ppm of both BA plus SA and pasteurizing the product at 85 °C could be recommended for lowering thiobarbituric acid (TBA), total volatile nitrogen (TVN), peroxide value (PV), free fatty acid (FFA), ammonia, saponification value and hence for inhibiting lipid oxidation and preventing rancidity to an extent up to nine days of refrigerated storage (4 °C). This level is also recommended as a preservative agent to inhibit the bacterial deterioration of chicken liver paste (Foie gras). A sensory evaluation showed that liver paste from chicken was very acceptable from the standpoint of taste, odor, appearance, color and texture. In comparison to liver paste from duck, the results proved that no significant differences were observed between the liver paste from chicken and duck liver paste.
Oleins as a source of estolides for biolubricant applications
Authors: García-Zapateiro L. A. , Delgado M. A. , Franco J. M. , Valencia C. , Ruiz-Méndez M. V. , Garcés R. , Gallegos C.
Published: February 2010

This study deals with the synthesis of estolides from high-oleic sunflower oil oleins, and its potential use as viscosity modifiers for biolubricant applications. Synthesis reactions were monitored for 24 h. Estolide molecular weight increased continuously with reaction time. Dynamic viscosities and densities of the different estolides were measured in a temperature range comprised between 10 and 120 °C. Maximum viscosities and estolide molecular weight were obtained after 12 h of reaction. However, the largest viscosity increments were observed within the first 3 hours of processing, due to a dramatic increase in the molecular weight of the estolides.
Variations in fatty acid composition, glucosinolate profile and some phytochemical contents in selected oil seed rape (Brassica napus L.) cultivars
Authors: El-Din Saad El-Beltagi Hossam , Amin Mohamed Amal
Published: February 2010

Rapeseed (Brassica napus L.) is now the third most important source of edible oil in the world after soybean and palm oil. In this study seeds of five different rapeseed cultivars namely; pactol, silvo, topas, serw 4 and serw 6 were evaluated for their fatty acid composition, glucosinolate profile, amino acids, total tocopherols and phenolic content. Among all cultivars significant variability in fatty acids were observed. The oleic acid (C18:1) ranged from 56.31% to 58.67%, linoleic acid (C18:2) from 10.52% to 13.74%, α-linolenic acid (C18:3) from 8.83% to 10.32% and erucic acid (22:1) from 0.15% to 0.91%. The glucosinolate profile of rapeseed was also separated and identified using high-performance liquid chromatography. Small variations in the glucosinolate profile were observed among all tested cultivars; however, progoitrin and gluconapin were the major glucosinolate found. Additionally, silvo cultivar showed the highest total glucosinolate c ontents (5.97 μmol/g dw). Generally, the contents of aspartic, glutamic, arginine and leucine were high, while the contents of tyrosine and isoleucine were low among all cultivars. For total tocopherols, the results indicated that both serw 6 and pactol cultivars had the highest total tocopherol contents (138.3 and 102.8 mg/100 g oil, respectively). Total phenolic contents varied from 28.0 to 35.4 mg/g dw. The highest total phenolic content was found in topas while the lowest value was detected in serw 6. These parameters; fatty acid contents, glucosinolate profile and amino acids together with total tocopherols and phenolic contents, could be taken into consideration by oilseed rape breeders as selection criteria for developing genotypes with modified seed quality traits in Brassica napus L.
Life Cycle Assessment (LCA) used to compare two different methods of ripe table olive processing
Authors: Russo Carlo , Cappelletti Giulio Mario , Martino Nicoletti Giuseppe
Published: February 2010

The aim of the present study is to analyze the most common method used for processing ripe table olives: the “California style”. Life Cycle Assessment (LCA) was applied to detect the “hot spots” of the system under examination. The LCA results also allowed us to compare the traditional “California style”, here called “method A”, with another “California style”, here called “method B”. We were interested in this latter method, because the European Union is considering introducing it into the product specification of the Protected Denomination of Origin (PDO) “La Bella della Daunia”. It was also possible to compare the environmental impacts of the two “California style” methods with those of the “Spanish style” method. From the comparison it is clear that “method B” has a greater environmental impact than “method A” because greater amounts of water and electricity are required, whereas “Spanish style” processing has a lower environmental impact than the ”California style” methods.
Modeling of an immobilized lipase tubular reactor for the production of glycerol and fatty acids from oils
Authors: Oddone Sebastián , Grasselli Mariano , Cuellas Anahí
Published: February 2010

Advances in the design of a bioreactor in the fats and oils industry have permitted the hydrolysis of triglycerides in mild conditions and improved productivity while avoiding the formation of unwanted byproducts. The present work develops a mathematical model that describes the hydrolytic activity of a tubular reactor with immobilized lipases for the production of glycerol and fatty acids from the oil trade. Runge Kutta’s numerical method of high order has been applied, considering that there is no accumulation of the substratum in the surface of the membrane, where the enzyme is. At the same time, different equations based on the kinetic model of Michaelis Mentens and the Ping-Pong bi-bi mechanism were examined. Experimental data in discontinuous systems are the basis for the development of the quantitative mathematical model that was used to simulate the process computationally. The obtained results allow for optimizing both the operative variables and the economic aspects of industrial processes.
Evaluation of the performance of Frying Oils using an ultrasonic technique
Authors: Izbaim D. , Faiz B. , Moudden A. , Taifi N. , Aboudaoud I.
Published: February 2010

The performance of unhydrogenated soybean oil (USBO) and partially hydrogenated soybean oil (PHSBO) was evaluated by comparing their frying stability. Ultrasonic velocity was used to evaluate the oils. Measurements of free fatty acids (FFA) and total polar compounds (TPC) are typical indexes of oil degradation. Oils were heated at 180 °C for periods of 8 h per day for 4 consecutive days. The results from the ultrasonic analyses show different influences of thermo-oxidation on USBO and PHSBO. The ultrasonic measurements had strong correlations with chemical changes. Consequently, the ultrasonic method is useful to obtain information on the quality of the used frying oils.
Physicochemical and spectroscopical investigation of Pequi (Caryocar coriaceum Wittm.) pulp oil
Authors: Sena Diniz M. , Rodrigues Fabíola F.G. , Freire Paulo T.C. , De Lima S. G. , Coutinho Henrique D.M. , Carvajal Juan C.L. , Da Costa José G.M.
Published: February 2010

This work describes the physicochemical characterization of the fruit pulp oil of Caryocar coriaceum (Wittm), “pequi.” The chemical composition was assessed by GLC, which demonstrated the following fatty acid contents: oleic (55.79%), palmitic (34.18%), heptadecenoic (5.86%), linoleic (1.80%), stearic (1.73%), eicosenoic (0.37%) and palmitoleic (0.27%). The vibrational spectroscopy results were typical of an edible oil, and are in accordance with the high unsaturated fatty acid content. Physical properties such as water content, acidity, peroxide index, saponification index, relative density, viscosity and refraction index are reported for the first time for this species. Pequi fruits have a high nutritional value, and are rich in protein and vitamins. In addition, their composition includes essential fatty acids, which accounts for the popular use of the fruit oil for antioxidant and antiinflammatory activity. There is great interest in extending the use of this natural product by exploiting the combined social, economic and therapeutic values of its derivatives.
Application of high-temperature gas chromatography to the analysis of used frying fats
Authors: Aguirre M. , Marmesat S. , Ruiz Méndez M. V. , Dobarganes M. C.
Published: February 2010

The determination of polar compounds is the most commonly applied technique in the analysis of used frying fats and oils. High-temperature gas chromatography allows for a quantitative determination of oxidized monomeric FAME and dimeric FAME thus giving extra information on oil degradation starting from the fraction of polar compounds. Polar compounds are transesterified and methyl esters are separated in a VF-5ht Ultimetal column (150 °C -held for 5 min- rising at 5 °C min-1 to 370 °C and held for 5 min) using methyl tricosanoate as internal standard. Results are compared with those obtained by more complex alternative methodology using high-performance size-exclusion chromatography.
An Educational Model for Asynchronous E-Learning. A Case Study in a Higher Technology Education
Authors: Papachristos Dimitris , Alafodimos Nikolaos , Arvanitis Konstantinos , Vassilakis Kostas , Kalogiannakis Michail , Kikilias Panagiotis , Zafeiri Evi
Published: February 2010

Nowadays, the use of Web based Education (WbE) in distance learning education is considered to be an innovative method of learning. Supportive parties argue that WbE renews the educational practice through the use of computers and their applied methodology, as well as the technologies provided by the use of the internet. These result in consciously renewing the educational material and in creating a flexible structure which promotes the individualization of learning. The proposed model aims at delivering technological classes through the internet, offering a flexible use of means and tools, allowing a synthetic presentation of selected bibliographic texts that cover the whole cognitional object, developing a cooperative spirit and individualising the learning procedure.
E-Teaching in E-Workplaces: The Affective Nexus
Authors: McIntosh Kenny John
Published: February 2010

This article outlines a small-scale phenomenological study of e-teachersâ?? experience of feelings about and while discharging professional responsibilities in online workplaces. Findings indicate that e-teachersâ?? consciousness of positive feelings is associated with enhanced self-perception of well-being and increased engagement in e-teaching, but that e-teachers are also conscious of feelings of disempowerment, isolation, vulnerability and frustration about and while working in e-workplaces and that those feelings impact detrimentally their sense of self as e-teachers, their participation in e-courses, their choice of e-teaching strategies, their interactions with e-learners and their self-efficacy as e-teachers. This suggests an affective nexus in being e-teachers and interacting as e-teachers. The significance of this affective nexus for e-teachersâ?? learning and continuing professional development is identified, and implications for those charged with overall responsibility for management of workplace conditions, workplace culture and employee well-being, as well as employee learning and professional development, are presented.
Evaluation of a Portable Automated Serum Chemistry Analyzer for Field Assessment of Harlequin Ducks,Histrionicus histrionicus
Authors: Stoskopf Michael K. , Mulcahy Daniel M. , Esler Daniel
Published: February 2010

A portable analytical chemistry analyzer was used to make field assessments of wild harlequin ducks (Histrionicus histrionicus) in association with telemetry studies of winter survival in Prince William Sound, Alaska. We compared serum chemistry results obtained on-site with results from a traditional laboratory. Particular attention was paid to serum glucose and potassium concentrations as potential indicators of high-risk surgical candidates based on evaluation of the field data. The median differential for glucose values (N=82) between methods was 0.6 mmol/L (quartiles 0.3 and 0.9 mmol/L) with the median value higher when assayed on site. Analysis of potassium on site returned a median of 2.7 mmol/L (N=88; quartiles 2.4 and 3.0 mmol/L). Serum potassium values were too low for quantitation by the traditional laboratory. Changes in several serum chemistry values following a three-day storm during the study support the value of on site evaluation of serum potassium to identify presurgical patients with increased anesthetic risk.
Chemoradiotherapy in pancreatic carcinoma
Authors: Pathy Sushmita , Chander Subhash
Published: February 2010

Pancreatic cancer patients present late in their course and surgical resection as a modality of treatment is of limited value. Majority develop loco-regional failure and distant metastasis, therefore, adjuvant therapy comprising of radiotherapy and chemotherapy are useful treatment options to achieve higher loco-regional control. Specialized irradiation techniques like intra-operative radiotherapy that help to increase the total tumor dose have been used, however, controvertible survival benefit was observed. Various studies have shown improved median and overall survival with chemoradiotherapy for advanced unresectable pancreatic carcinoma. The role of new agents such as topoisomerase I inhibitors also needs further clinical investigations.
Pourbaix Diagrams for Nickel in Concentrated Aqueous Lithium Bromide Solutions at 25°C
Authors: Muñoz-Portero M. J. , García-Antón J. , Guiñón J. L. , Pérez-Herranz V.
Published: February 2010

Pourbaix diagrams (electrode potential-pH diagrams) for the Ni-Br−-H2O system at 25°C were developed in 400-g/L, 700-g/L, and 850-g/L (4.61-M, 8.06-M, and 9.79-M) lithium bromide (LiBr) solutions, which are common concentrations found in different parts of absorption devices. The diagrams were compared with the simple Ni-H2O system at 25°C. Pourbaix diagrams were constructed from standard Gibbs free energy of formation (ΔGfo) data at 25°C for all the species considered. Conventional procedures were followed to calculate the electrochemical and chemical equilibria from ΔGfo data Equilibria for the Ni-Br−-H2O system at 25°C were determined for bromide ion activities of 15.61, 194.77, and 650.06, which corresponded to the 400-g/L, 700-g/L, and 850-g/L LiBr solutions, respectively. Activities of all the dissolved species containing nickel were plotted for 10−6, 10−4, 10−2, and 100. Comparison of the simple Ni-H2O system at 25°C with the diagrams illustrating the effect of Br− activity showed that the formation of aqueous NiBr2(aq) extended the nickel solubility range to both higher pH values and lower potentials, particularly in acid, neutral, and weak alkaline areas of the diagrams, as a result of destabilization of β-Ni(OH)2, and promotion of a more active behavior of nickel. The effect was enhanced at higher bromide ion activities.
Pitting Corrosion and its Countermeasures for Pressurized Water Reactor Steam Generator Tubes
Authors: Hur D. H. , Choi M. S. , Lee D. H. , Song M. H. , Han J. H.
Published: February 2010

Pitting corrosion was the primary cause of the Alloy 600 (UNS N06600) steam generator tube degradation in a Korean pressurized water reactor (PWR) plant. Pulled tube examinations and remedial measures were carried out to mitigate the pitting. Based on the destructive examinations, the main causes of pitting corrosion were considered to be the following: accumulated sludge with a high copper content due to corrosion of copper alloys in the secondary system, acidic crevice conditions caused by chloride from condenser leakage, and ingress of air during layup. Countermeasures such as copper alloy replacement, water chemistry control, and chemical cleaning were implemented to mitigate the pitting. Chemical cleaning was evaluated as the most effective.
Role of Wood Extractives in Black Liquor Corrosiveness
Authors: Hazlewood P. E. , Singh P. M. , Hsieh J. S.
Published: February 2010

In the pulp and paper industry, variability in the process and wood source may result in highly corrosive waste liquors, called black liquors, from the Kraft pulping process. Prior research has demonstrated corrosion rates of carbon steel in pulp mill equipment ranging from <0.03 mm/y to >2.54 mm/y, depending on the wood species pulped. In this study wood species-dependent corrosion is confirmed and age-dependent corrosion is investigated as a function of organic extractive content. The composition of the organic portion of black liquor depends largely on the wood species used. Organic components come from extractives in the wood chips or are generated from the degradation of lignin and other wood constituents during the pulping process. Depending upon the wood species used, some black liquor constituents have been identified to increase the corrosiveness of black liquors whereas others may act as corrosion inhibitors. Our research demonstrates the importance of operational parameters for wood species and wood chip usage and delivery to downstream process corrosion. Further, results show the importance of water-extracted organics in wood, such as long chain fatty acids, using a novel methodology for the separation of extractives and lignin breakdown products in the testing of black liquor corrosiveness with carbon steel A516-Grade 70 (UNS K02700).
Improved Corrosion Protection of Aluminum Alloys by System Approach Interface Engineering: Part 2—AA2024-T3
Authors: Yu Q. S. , Reddy C. M. , Moffitt C. E. , Wieliczka D. M. , Johnson R. , Deffeyes J. E. , Yasuda H. K.
Published: February 2010

This study investigates the development of a chromate-free corrosion protection system for AA2024-T3 ([2B]) based on the concept of system approach interface engineering (SAIE) by chemical and plasma techniques. An anode magnetron-enhanced direct current (DC) cathodic plasma process was used to enhance the bonding to and the protection offered by a cathodically electrodeposited epoxy-based primer (E-coat) on [2B]. Corrosion test results of SO2 and Prohesion salt spray tests indicated that superior corrosion protection properties of [2B] were achieved with the aid of plasma interface engineering, tailoring specific properties of the interfaces. Many of these plasma polymer-enhanced systems on [2B] outperformed the controls used in this study: chromate conversion coated and then primer (Deft 44-GN-36) coated [2B], as well as chromate conversion coated and then cathodic E-coated [2B]. The corrosion protection properties of [2B] were strongly dependent on the surface preparation of the alloy, which was investigated by x-ray photoelectron spectroscopy (XPS). Plasma polymer-coated systems prepared on alkaline-cleaned [2B] surfaces displayed enhanced corrosion protection properties.
Preparation of Protective Films Containing Molybdate for Self-Healing of a Scratched Iron Surface
Authors: Aramaki K.
Published: February 2010

Nonchromate, self-healing films protective against corrosion of Fe were assessed by polymerization of 1,2-bis(triethoxysilyl)ethane ([C2H5O]3Si[CH2]2-Si(OC2H5]3; BTESE) containing ammonium heptamolybdate ([NH4]6Mo7O244H2O), which was combined tightly with ferric ion (Fe3+) on the surface of an Fe electrode passivated in aerated 0.1 M sodium molybdate (Na2MoO4). After the electrode surface was scratched crosswise with a knife-edge, the electrode was immersed in an aerated 0.1 M sodium chloride (NaCl) solution at 30°C for > 4 h, and then polarization curves were measured in the solution potentiodynamically. The anodic process of Fe corrosion was suppressed markedly by passivation of the scratched surface with molybdate ion (MoO42−) oozing from the film and O2 diffusing through the scratch. The surface covered with the film was characterized by x-ray photoelectron spectroscopy, Fourier transform infrared reflection spectroscopy, and electron probe microanalysis.
Comparative Analysis of Electrochemical Noise Generated During Stress Corrosion Cracking of AISI 304 Stainless Steel
Authors: Leban M. , Doleček V. , Legat A.
Published: February 2010

Electrochemical noise measurements were performed on electrodes made from a sample of AISI 304 (UNS S30400) stainless steel. Potential and current noise were measured under open-circuit conditions in a three-electrode system, one of the electrodes being maintained under load and acting as a working electrode. Two types of electrode set-ups were used, which differed according to the method of load application. In the first case, the common electrode was a U-bend test specimen, which was subjected to a static, large, but undefined load. In the second case, it was a tensile test specimen, which was subjected to a gradually increasing load (the slow rate load test [SRLT]). U-bend tests were performed in a concentrated solution of magnesium chloride (MgCl2) at an elevated temperature, test specimens being dismantled and examined daily through a microscope. SRLT were conducted in a dilute solution of sodium thiocyanate (NaSCN) at room temperature, with simultaneous electrochemical noise (ECN) and load/elongation measurements. Toward the end of both types of tests, significant simultaneous spikes of voltage and current noise were observed. The spikes detected during SRLT correlated with drops in the applied load and sudden increases in elongation. After the tests were completed, several characteristic ECN time series, referring to both types of test specimen, were subjected to spectral and chaos analysis. Attempts to distinguish between the active cracking and nonactive cracking periods on the basis of the aforementioned types of analysis were unsuccessful since, in the case of the U-bend tests, the events that are typical for stress corrosion cracking (SCC) processes were too rare. In the case of the SRLT, the ECN time series were not stationary, which is a necessary condition for a successful outcome of such analyses.
Microbiologically Influenced Corrosion of Copper in Potable Water Systems—pH Effects
Authors: Webster B. J. , Werner S. E. , Wells D. B. , Bremer P. J.
Published: February 2010

Copper tubing used in potable water plumbing systems occasionally experiences reactions that lead to the release of copper corrosion by-products into the water. The main factor controlling microbiologically influenced corrosion (MIC) of copper has been identified as a decrease in pH, which in conjunction with the incorporation of bacterially produced extracellular polymeric substances (EPS) in the copper oxide film, decreases the protective nature of the film. The biofilm (bacteria and EPS) is believed to have a secondary role to the nature of the oxide film in controlling the rate of corrosion. MIC was produced in laboratory reactors containing copper electrodes exposed to simulated potable water in the presence of a biofilm composed of microorganisms isolated from afield site. In the presence of the biofilm, small but significant reductions in pH occurred—from an initial value of 7.5 to between 6.5 and 6.9. Using electrochemical impedance spectroscopy (EIS), it was shown that the presence of a biofilm caused instances of higher corrosion rates similar to those measured in inorganic tests atpH 6.8. Modeling the oxide film as a thin barrier layer covered by a porous layer, EIS data revealed similarities between the oxide structure on samples experiencing MIC to samples exposed in sterile tests at pH 6.8.
Inhibition of Filiform Corrosion on Organic-Coated Aluminum Alloy by Hydrotalcite-Like Anion-Exchange Pigments
Authors: McMurray H. N. , Williams G.
Published: February 2010

Novel anion-exchange anticorrosion pigments consisting of nitrate-, carbonate-, and chromate-exchanged hydrotalcite (HT) are shown to inhibit the propagation of filiform corrosion (FFC) effectively on organic-coated aluminum alloy 2024-T3 (AA2024-T3 [UNS A92024]) alloy. The HT-pigments are dispersed in polyvinyl butyral (PVB) coatings applied to the AA2024-T3 surface. Following FFC initiation by application of controlled amounts of aqueous hydrochloric acid (HCl) to a penetrative coating defect, the time-dependent extent of coating delamination is determined both optically and by repeated in-situ scanning using a scanning Kelvin probe (SKP) apparatus. All the HT-pigments profoundly reduce rates of coating delamination by comparison to unpigmented samples. However, inhibitor efficiency is dependent upon the exchangeable anion and increases in the order: carbonate < nitrate < chromate. It is also shown that by using SKP potentiometry, exchangeable chromate anions interact specifically with the metal surface to depress free corrosion potential values.
Corrosion Protection of Aluminum Alloy 2024-T3 by Vanadate Conversion Coatings
Authors: Guan H. , Buchheit R. G.
Published: February 2010

In this paper, the formation, chemistry, morphology, and corrosion protection of a new type of inorganic conversion coating is described. This coating, referred to as a vanadate conversion coating (VCC), forms on aluminum alloy substrates in a matter of minutes during simple immersion in aqueous vanadate-based solutions at ambient temperatures. VCCs are yellow in color and conformal across the surface of aluminum alloy 2024-T3 (AA2024-T3 [UNS A92024]) substrates. Auger electron sputter depth profiles and x-ray absorption near-edge spectroscopy show that VCCs formed by a 3-min immersion are 300 nm to 500 nm thick and consist of a mixture of vanadium oxides and other components in the coating bath. In anodic polarization experiments conducted in aerated chloride solutions, VCCs increase the pitting potential and decrease the rate of oxygen reduction. When characterized by electrochemical impedance spectroscopy, VCCs demonstrate a low-frequency impedance between 1 MΩ-cm2 and 2 MΩ-cm2 after 24 h exposure to aerated 0.5 M sodium chloride (NaCl) solutions. In salt spray testing conducted according to ASTM B117, VCCs suppress formation of large pits for more than 168 h. VCCs also appear to be self-healing. Analysis of solution in contact with VCCs by inductively coupled plasma emission spectroscopy indicates that vanadate is released into solution upon exposure. Vanadium deposits were identified by x-ray microchemical analysis on a bare alloy substrate held in close proximity to a vanadate conversion-coated surface, and corrosion resistance of this bare surface was observed to increase during exposure. An important component of VCC formation appears to involve inorganic polymerization of V5+, which leads to the buildup of a film that passivates the surface and inhibits corrosion.
Electrochemical Studies on High-Temperature Corrosion of Silicon-Iron Coatings and Iron Aluminide Intermetallic Alloys by Molten Salts
Authors: Amaya M. , Porcayo-Calderon J. , Martinez L.
Published: February 2010

The performance of Fe-Si coatings and an iron aluminide (FeAl) intermetallic alloy (FeAl40at%+0.1at%B+10vol%Al2O3) in molten salts containing vanadium pentoxide (V2O5) and sodium sulfate (Na2SO4) is reported. Corrosion and fouling by ash deposits containing V2O5 and Na2SO4 are typical corrosion problems in fuel oil-fired electric power units. High-temperature corrosion tests were performed using both electrochemical polarization and immersion techniques. The temperature interval of this study was 600°C to 900°C, and the molten salts were 80wt%V2O5-20wt%Na2SO4. Curves of corrosion current density vs temperature obtained by the potentiodynamic studies are reported, as well as the weight loss vs temperature curves from molten salt immersion tests. Both Fe-Si coatings and FeAl40at%+0.1at%B+10vol%Al2O3 showed good behavior against molten salt corrosion. The final results show the potential of these coatings and alloys to solve the high-temperature corrosion in fuel oil-fired electric power units.
Initiation and Growth of Stress Corrosion Cracks in Type 316L Stainless Steel During Slow Strain Rate Testing
Authors: Haruna T. , Shibata T.
Published: February 2010

The initiation and growth of cracks in type 316L (UNS S31603) stainless steel (SS) in a chloride solution containing thiosulfate ions (S2O32−) during slow strain rate testing (SSRT) were analyzed on the basis of fracture mechanics. Crack behavior on the specimen surface was observed in situ using a charge-coupled device (CCD) camera with a videotape recording system. Three types of specimens were used: a single-notched plate, a smooth cylinder, and a smooth plate. The single-notched specimen failed to produce a sharp crack similar to that formed on the smooth specimens. For the smooth specimens, the stress intensity factor (KISCC) was found to vary from 3.9 MN/m3/2 to 5.0 MN/m3/2, and the crack growth rate ranged from 5.2 × 10−9 m/s to 1.0 × 10−8 m/s, which approximately agreed with data determined by other authors using a fracture mechanics approach. Thus, the SSRT combined with the in situ observation technique was useful in analyzing the crack initiation and growth process.
Quantitative Assessment of Localized Corrosion Occurring on Galvanized Steel Samples Using the Scanning Vibrating Electrode Technique
Authors: Worsley D. A. , McMurray H. N. , Sullivan J. H. , Williams I. P.
Published: February 2010

Zinc and zinc alloy galvanized steel is used increasingly for structural cladding, automotive, and domestic appliance applications. In assessing the different galvanizing coatings, it is important to understand the nature of corrosion reactions occurring on the metal surfaces. To this end, the scanning vibrating electrode technique (SVET) has been used to study the effect of variation in metallic coating on the localization and intensity of corrosion reactions occurring on the bare metal surfaces when immersed in aerated 0.1% sodium chloride (NaCl). The samples used comprised pure zinc and galvanized steel substrates, namely electro-zinc (EZ), hot dip galvanized steel (HDG), iron (9%) zinc intermetallic (IZ), 5% aluminum zinc alloy (Galfan), and 55% aluminum zinc alloy (Zalutite). The SVET has the resolution and sensitivity to enable the number and intensity of active anodes to be quantified. Zinc galvanized materials show anodes, which do not deactivate within the 24 h of the test whereas zinc aluminum alloy anodes display typical anode lifetimes of 6 h to 12 h. The SVET data has been calibrated and integrated to provide a total current per scan and subsequently converted to zinc loss using Faraday's law. The total average mass losses obtained from 10-mm by 10-mm exposed areas were measured using the SVET: 1.133, 0.601, 0.432, 0.615, 0.264, and 0.051 mg for zinc, EZ, HDG, IZ, Galfan, and Zalutite, respectively, and these values were confirmed using inductively coupled plasma mass spectrometry (ICP-MS). The SVET data for zinc loss obtained over 24 h has been compared to external weathering data obtained after 2, 6, and 12 months of external exposure. There is an excellent correlation between metal runoff in initial external exposure and 24-h SVET experiments. In longer-term exposure, however, the IZ coating becomes covered in a metal hydr(oxide) layer, reducing runoff, and penetrative defects to the iron substrate in EZ lead to elevated runoff rates within 12 months.
Influence of Cathodic and Anodic Currents on Cavitation Erosion
Authors: Auret J. G. , Damm O. F. R. A. , Wright G. J. , Robinson F. P. A.
Published: February 2010

A vibratory-type cavitation test rig was constructed to study the effect of polarizing currents applied to a cavitating body. The generation of gas by electrolysis reduced mechanical damage suffered by a cavitating body because of bubble collapse cushioning. However, the net effect on overall damage depended on several factors, including the intensity of mechanical attack, corrosion rate, and surface geometrical effects. A cathodic current was shown to always decrease of the total volume loss rate, but the volume loss rate sometimes was increased and sometimes was reduced in the anodic current range.
Corrosion of Nickel-Based Alloys in Acidified Lithium Chloride Solutions
Authors: Pawel S. J.
Published: February 2010

Immersion tests were performed on nickel (Ni)-based alloys in acidified 2 M lithium chloride (LiCl) solutions as a function of temperature and pH. Results indicated alloy C-22 (UNS N06022) and alloy C-276 (UNS N10276) were very resistant to corrosion in this environment to pH 1 at 95°C. Other alloys revealed extreme corrosion at low pH (alloy G-30 [UNS N06030] and alloy 20Mo6 [UNS N08026]) or accelerated corrosion due to solution aeration (alloy B-2 [UNS N10665]) and were not recommended for the process described. Failures of C-276 in similar service environments were attributed to poor control of process pH, with values ≤ 0.5 leading to extreme general corrosion.