General and Localized corrosion of Austenitic and Borated Stainless Steels in Simulated Concentrated Ground Waters

Boron containing stainless steels are used in the nuclear industry for applications such as spent fuel storage, control rods and shielding. It was of interest to compare the corrosion resistance of three borated stainless steels with standard austenitic alloy materials such as type 304 and 316 stainless steels. Tests were conducted in three simulated concentrated ground waters at 90 C. Results show that the borated stainless were less resistant to corrosion than the witness austenitic materials. An acidic concentrated ground water was more aggressive than an alkaline concentrated ground water

Assessment of spray polyurethane foam worker exposure to organophosphate flame retardants through measures in air, hand wipes, and urine

Tris(1-chloro-2-propyl) phosphate (TCPP, also referenced as TCIPP), a flame retardant used in spray polyurethane foam insulation, increases cell toxicity and affects fetal development. Spray polyurethane foam workers have the potential to be exposed to TCPP during application. In this study, we determined exposure to TCPP and concentrations of the urinary biomarker bis(1-chloro-2-propyl) phosphate (BCPP) among 29 spray polyurethane foam workers over 2 work days. Work was conducted at residential or commercial facilities using both open-cell (low density) and closed-cell (high density) foam. Study participants provided two personal air samples (Day 1 and Day 2), two hand wipe samples (Pre-shift Day 2 and Post-shift Day 2), and two spot urine samples (Pre-shift Day 1 and Post-shift Day 2). Bulk samples of cured spray foam were also analyzed. Sprayers were found to have significantly higher TCPP geometric mean (GM) concentration in personal air samples (87.1 mu g/m(3)), compared to helpers (30.2 mu g/m(3); p = 0.025). A statistically significant difference was observed between TCPP pre- and post-shift hand wipe GM concentrations (p = 0.004). Specifically, TCPP GM concentration in post-shift hand wipe samples of helpers (106,000 ng/sample) was significantly greater than pre-shift (27,300 ng/sample; p \u3c 0.001). The GM concentration of the urinary biomarker BCPP (23.8 mu g/g creatinine) was notably higher than the adult male general population (0.159 mu g/g creatinine, p \u3c 0.001). Urinary BCPP GM concentration increased significantly from Pre-shift Day 1 to Post-shift Day 2 for sprayers (p = 0.013) and helpers (p = 0.009). Among bulk samples, cured open-cell foam had a TCPP GM concentration of 9.23% by weight while closed-cell foam was 1.68%. Overall, post-shift BCPP urine concentrations were observed to be associated with TCPP air and hand wipe concentrations, as well as job position (sprayer vs. helper). Spray polyurethane foam workers should wear personal protective equipment including air-supplied respirators, coveralls, and gloves during application

The effect of water vapor on the corrosion of carbon steel at 65{degree}C

AISI 1020 carbon steel was exposed to air at various relative humidities at 65{degrees}C. A ``critical relative humidity`` (CRH) of 75--85% was determined. The CRH is the transitional relative humidity where oxidation/corrosion changes from dry oxidation to aqueous film electrochemical corrosion. Short term testing suggests that aqueous film electrochemical corrosion results in the formation of an inner oxide of Fe{sub 3}O{sub 4}, and an outer oxide of a powdery Fe{sub 2}O{sub 3} and/or Fe{sub 2}O{sub 3}{center_dot}xH{sub 2}O

Assessment of Spray Polyurethane Foam Worker Exposure to Organophosphate Flame Retardants Through Measures in Air, Hand Wipes, and Urine

Tris(1-chloro-2-propyl) phosphate (TCPP, also referenced as TCIPP), a flame retardant used in spray polyurethane foam insulation, increases cell toxicity and affects fetal development. Spray polyurethane foam workers have the potential to be exposed to TCPP during application. In this study, we determined exposure to TCPP and concentrations of the urinary biomarker bis(1-chloro-2-propyl) phosphate (BCPP) among 29 spray polyurethane foam workers over 2 work days. Work was conducted at residential or commercial facilities using both open-cell (low density) and closed-cell (high density) foam. Study participants provided two personal air samples (Day 1 and Day 2), two hand wipe samples (Pre-shift Day 2 and Post-shift Day 2), and two spot urine samples (Pre-shift Day 1 and Post-shift Day 2). Bulk samples of cured spray foam were also analyzed. Sprayers were found to have significantly higher TCPP geometric mean (GM) concentration in personal air samples (87.1 μg/m3), compared to helpers (30.2 μg/m3; p = 0.025). A statistically significant difference was observed between TCPP pre- and post-shift hand wipe GM concentrations (p = 0.004). Specifically, TCPP GM concentration in post-shift hand wipe samples of helpers (106,000 ng/sample) was significantly greater than pre-shift (27,300 ng/sample; p \u3c 0.001). The GM concentration of the urinary biomarker BCPP (23.8 μg/g creatinine) was notably higher than the adult male general population (0.159 μg/g creatinine, p \u3c 0.001). Urinary BCPP GM concentration increased significantly from Pre-shift Day 1 to Post-shift Day 2 for sprayers (p = 0.013) and helpers (p = 0.009). Among bulk samples, cured open-cell foam had a TCPP GM concentration of 9.23% by weight while closed-cell foam was 1.68%. Overall, post-shift BCPP urine concentrations were observed to be associated with TCPP air and hand wipe concentrations, as well as job position (sprayer vs. helper). Spray polyurethane foam workers should wear personal protective equipment including air-supplied respirators, coveralls, and gloves during application

Corrosion Rate of Alloy 22 as a Function of Immersion Time

Alloy 22 (N06022) is a nickel (Ni) based alloy containing nominally 22% Chromium (Cr), 13% Molybdenum (Mo) and 3% tungsten (W). Alloy 22 is highly resistant to general and localized corrosion such as pitting corrosion and stress corrosion cracking. Due to the formation of a stable passive film, when Alloy 22 is immersed in certain electrolytes, its corrosion potential (E{sub corr}) increases and its corrosion rate (CR) decreases as a function of the immersion time. This paper discusses the evolution of E{sub corr} and corrosion rate (CR) of creviced Alloy 22 specimens in six different mixtures of sodium chloride (NaCl) and potassium nitrate (KNO{sub 3}) at 100 C. Two types of specimens were used, polished as-welded (ASW) and as-welded solution plus heat-treated (ASW+SHT). The latter contained the black annealing oxide film on the surface. Results show that, for the two type of materials, as the immersion time increases, E{sub corr} increased and the CR decreased. Even for concentrated brine solutions at 100 C the CR was < 50 nm/year after more than 100 days immersion

Active surveillance for rheumatic heart disease in endemic regions: a systematic review and meta-analysis of prevalence among children and adolescents

Background Rheumatic heart disease accounts for up to 250 000 premature deaths every year worldwide and can be regarded as a physical manifestation of poverty and social inequality. We aimed to estimate the prevalence of rheumatic heart disease in endemic countries as assessed by diff erent screening modalities and as a function of age. Methods We searched Medline, Embase, the Latin American and Caribbean System on Health Sciences Information, African Journals Online, and the Cochrane Database of Systematic Reviews for population-based studies published between Jan 1, 1993, and June 30, 2014, that reported on prevalence of rheumatic heart disease among children and adolescents (≥5 years to <18 years). We assessed prevalence of clinically silent and clinically manifest rheumatic heart disease in random eff ects meta-analyses according to screening modality and geographical region. We assessed the association between social inequality and rheumatic heart disease with the Gini coeffi cient. We used Poisson regression to analyse the eff ect of age on prevalence of rheumatic heart disease and estimated the incidence of rheumatic heart disease from prevalence data. Findings We included 37 populations in the systematic review and meta-analysis. The pooled prevalence of rheumatic heart disease detected by cardiac auscultation was 2·9 per 1000 people (95% CI 1·7–5·0) and by echocardiography it was 12·9 per 1000 people (8·9–18·6), with substantial heterogeneity between individual reports for both screening modalities (I²=99·0% and 94·9%, respectively). We noted an association between social inequality expressed by the Gini coeffi cient and prevalence of rheumatic heart disease (p=0·0002). The prevalence of clinically silent rheumatic heart disease (21·1 per 1000 people, 95% CI 14·1–31·4) was about seven to eight times higher than that of clinically manifest disease (2·7 per 1000 people, 1·6–4·4). Prevalence progressively increased with advancing age, from 4·7 per 1000 people (95% CI 0·0–11·2) at age 5 years to 21·0 per 1000 people (6·8–35·1) at 16 years. The estimated incidence was 1·6 per 1000 people (0·8–2·3) and remained constant across age categories (range 2·5, 95% CI 1·3–3·7 in 5-year-old children to 1·7, 0·0–5·1 in 15-year-old adolescents). We noted no sexrelated diff erences in prevalence (p=0·829). Interpretation We found a high prevalence of rheumatic heart disease in endemic countries. Although a reduction in social inequalities represents the cornerstone of community-based prevention, the importance of early detection of silent rheumatic heart disease remains to be further assessed

Integrated Corrosion Facility for long-term testing of candidate materials for high-level radioactive waste containment

A long-term-testing facility, the Integrated Corrosion Facility (I.C.F.), is being developed to investigate the corrosion behavior of candidate construction materials for high-level-radioactive waste packages for the potential repository at Yucca Mountain, Nevada. Corrosion phenomena will be characterized in environments considered possible under various scenarios of water contact with the waste packages. The testing of the materials will be conducted both in the liquid and high humidity vapor phases at 60 and 90{degrees}C. Three classes of materials with different degrees of corrosion resistance will be investigated in order to encompass the various design configurations of waste packages. The facility is expected to be in operation for a minimum of five years, and operation could be extended to longer times if warranted. A sufficient number of specimens will be emplaced in the test environments so that some can be removed and characterized periodically. The corrosion phenomena to be characterized are general, localized, galvanic, and stress corrosion cracking. The long-term data obtained from this study will be used in corrosion mechanism modeling, performance assessment, and waste package design. Three classes of materials are under consideration. The corrosion resistant materials are high-nickel alloys and titanium alloys; the corrosion allowance materials are low-alloy and carbon steels; and the intermediate corrosion resistant materials are copper-nickel alloys

Long Term Corrosion Potential and Corrosion Rate of Creviced Alloy 22 in Chloride Plus Nitrate Brines

Alloy 22 is a nickel base alloy highly resistant to all forms of corrosion. In conditions where tight crevices exist in hot chloride containing solutions and at anodic potentials, Alloy 22 may suffer crevice corrosion, a form of localized attack. The occurrence (or not) of crevice corrosion in a given environment (e.g. salt concentration and temperature), is governed by the values of the critical potential (E{sub crit}) for crevice corrosion and the corrosion potential (E{sub corr}) that the alloy may establish in the studied environment. If E{sub corr} is equal or higher than E{sub crit}, crevice corrosion may be expected. In addition, it is generally accepted that as Alloy 22 becomes passive in a certain environment, its E{sub corr} increases and its corrosion rate (CR) decreases. This paper discusses the evolution of E{sub corr} and corrosion rate (CR) of creviced Alloy 22 specimens in six different mixtures of sodium chloride (NaCl) and potassium nitrate (KNO{sub 3}) at 100 C. The effect of immersion time on the value of E{sub crit} was also determined. Two types of specimens were used, polished as-welded (ASW) and as-welded plus solution heat-treated (ASW+SHT). The latter contained the black annealing oxide film on the surface. Results show that, as the immersion time increases, E{sub corr} increased and the CR decreased. Even for highly concentrated brine solutions at 100 C the CR was &lt; 30 nm/year after more than 250 days immersion. Some of the exposed specimens (mainly the SHT specimens) suffered crevice corrosion at the open circuit potential in the naturally aerated brines. Immersion times of over 250 days did not reduce the resistance of Alloy 22 to localized corrosion

Getting it right when budgets are tight: Using optimal expansion pathways to prioritize responses to concentrated and mixed HIV epidemics.

BACKGROUND: Prioritizing investments across health interventions is complicated by the nonlinear relationship between intervention coverage and epidemiological outcomes. It can be difficult for countries to know which interventions to prioritize for greatest epidemiological impact, particularly when budgets are uncertain. METHODS: We examined four case studies of HIV epidemics in diverse settings, each with different characteristics. These case studies were based on public data available for Belarus, Peru, Togo, and Myanmar. The Optima HIV model and software package was used to estimate the optimal distribution of resources across interventions associated with a range of budget envelopes. We constructed "investment staircases", a useful tool for understanding investment priorities. These were used to estimate the best attainable cost-effectiveness of the response at each investment level. FINDINGS: We find that when budgets are very limited, the optimal HIV response consists of a smaller number of 'core' interventions. As budgets increase, those core interventions should first be scaled up, and then new interventions introduced. We estimate that the cost-effectiveness of HIV programming decreases as investment levels increase, but that the overall cost-effectiveness remains below GDP per capita. SIGNIFICANCE: It is important for HIV programming to respond effectively to the overall level of funding availability. The analytic tools presented here can help to guide program planners understand the most cost-effective HIV responses and plan for an uncertain future

Anodic Behavior of Alloy 22 in High Nitrate Brines at Temperatures Higher than 100(degree)C

Alloy 22 (N06022) may be susceptible to crevice corrosion in chloride solutions. Nitrate acts as an inhibitor to crevice corrosion. Several papers have been published regarding the effect of nitrate on the corrosion resistance of Alloy 22 at temperatures 100 C and lower. However, very little is known about the behavior of this alloy in highly concentrated brines at temperatures above 100 C. In the current work, electrochemical tests have been carried out to explore the anodic behavior of Alloy 22 in high chloride high nitrate electrolytes at temperatures as high as 160 C at ambient atmospheres. Even though Alloy 22 may adopt corrosion potentials in the order of +0.5 V (in the saturated silver chloride scale), it does not suffer crevice corrosion if there is high nitrate in the solution. That is, the inhibitive effect of nitrate on crevice corrosion is active for temperatures higher than 100 C