Examination and prediction of corrosion fatigue damage and inhibition

2017 ◽  
Vol 35 (4-5) ◽  
pp. 355-363
Author(s):  
Sarah E. Galyon Dorman ◽  
Justin W. Rausch ◽  
Saravanan Arunachalam ◽  
Scott A. Fawaz
Keyword(s):  
Fatigue Damage ◽  
Corrosion Fatigue ◽  
Mechanical Damage ◽  
Corrosion Damage ◽  
The United States ◽  
United States Department ◽  
Management Philosophy ◽  
Weapon Systems ◽  
Calcium Molybdate ◽  
Crack Transition

AbstractThe United States Department of Defense (DoD) estimated that the annual cost of corrosion to weapon systems and infrastructure in 2014 exceeded $18 billion and that the number was likely to continue to rise. Corrosion affects military readiness by taking critical weapon systems out of action, due to the degradation of equipment. Unfortunately, as the warfighters demand more from their systems, corrosion prevention and control is frequently traded during the acquisition cycle for weapon system performance. As a result, the DoD remains entrenched in a find-and-fix corrosion management philosophy which is expensive and unsustainable. Better standardized laboratory procedures are needed to help the DoD develop (1) a fundamental understanding of corrosion damage, (2) material performance data relevant to corrosion damage, (3) prediction methodologies to help mitigate the effects of corrosion nucleated damage and (4) to develop an understanding of how corrosion preventative coatings can slow mechanical damage. This paper addresses the effect of the corrosion inhibitors strontium chromate and calcium molybdate in concentrations relevant to service on corrosion fatigue damage as well as presents development of a test methodology for the examination of the corrosion pit-to-fatigue crack transition to help the DoD improve corrosion protection system selection.

The Effect of Corrosion Inhibitors on Environmental Fatigue Crack Growth in Al-Zn-Mg-Cu

2014 ◽  
Vol 891-892 ◽  
pp. 230-235
Author(s):  
Sarah E. Galyon Dorman
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Corrosion Fatigue ◽  
Corrosion Inhibitors ◽  
Corrosion Damage ◽  
The United States ◽  
Polymer Coatings ◽  
Fatigue Tests ◽  
Corrosion Prevention

Corrosion fatigue is an area of concern for the United States Air Force (USAF) and other Department of Defense (DoD) organizations. Often DoD corrosion prevention systems include chromate containing coatings, typically in the form of chromate conversion coatings and polymer primers. Chromate has been used successfully for many years within the DoD to prevent corrosion damage. However the environmental and personnel risks associated with chromate coatings have caused the USAF to pursue non-chromate containing corrosion prevention coatings [1]. To fully quantify chromate replacement coatings, an understanding of the effects that chromate has on corrosion fatigue crack growth rates must be fully characterized. Some researchers have shown that high levels of chromate added to 0.6 M NaCl full immersion corrosion fatigue tests on 7xxx series aluminum alloys slow the fatigue crack growth rate substantially [2,3]. The limitation of that research was that the amount of chromate present in the test solution environment was not connected to expected leach rates of chromate from polymeric coatings and a high solubility salt was used. The majority of DoD assets are protected from corrosion by polymer coatings loaded with corrosion inhibitors. For these coatings to slow fatigue crack propagation the corrosion inhibitors must become mobile as a consequence of hydration of the polymer coating matrix. Based on this mechanism of corrosion inhibitor release, the examination of atmospheric corrosion fatigue becomes important to help understand how inhibitors work in real world situations with hydrated salt layers rather than only fully immersed solutions.

Demonstrating Nutrient Cost Gradients: A Brooklyn Case Study

2014 ◽  
Vol 84 (5-6) ◽  
pp. 244-251 ◽  
Author(s):  
Robert J. Karp ◽  
Gary Wong ◽  
Marguerite Orsi
Keyword(s):  
Low Income ◽  
Energy Content ◽  
Food Selection ◽  
The United States ◽  
United States Department ◽  
Micronutrient Deficiencies ◽  
Caloric Density ◽  
Low Income Families ◽  
The Cost ◽  
The Impact

Abstract. Introduction: Foods dense in micronutrients are generally more expensive than those with higher energy content. These cost-differentials may put low-income families at risk of diminished micronutrient intake. Objectives: We sought to determine differences in the cost for iron, folate, and choline in foods available for purchase in a low-income community when assessed for energy content and serving size. Methods: Sixty-nine foods listed in the menu plans provided by the United States Department of Agriculture (USDA) for low-income families were considered, in 10 domains. The cost and micronutrient content for-energy and per-serving of these foods were determined for the three micronutrients. Exact Kruskal-Wallis tests were used for comparisons of energy costs; Spearman rho tests for comparisons of micronutrient content. Ninety families were interviewed in a pediatric clinic to assess the impact of food cost on food selection. Results: Significant differences between domains were shown for energy density with both cost-for-energy (p < 0.001) and cost-per-serving (p < 0.05) comparisons. All three micronutrient contents were significantly correlated with cost-for-energy (p < 0.01). Both iron and choline contents were significantly correlated with cost-per-serving (p < 0.05). Of the 90 families, 38 (42 %) worried about food costs; 40 (44 %) had chosen foods of high caloric density in response to that fear, and 29 of 40 families experiencing both worry and making such food selection. Conclusion: Adjustments to USDA meal plans using cost-for-energy analysis showed differentials for both energy and micronutrients. These differentials were reduced using cost-per-serving analysis, but were not eliminated. A substantial proportion of low-income families are vulnerable to micronutrient deficiencies.

Unifying Calibration Parameters for Dielectric Moisture Meter

2006 ◽  
Vol 2 (1) ◽  
pp. 73-94 ◽  
Author(s):  
Péter Mészáros ◽  
David B. Funk
Keyword(s):  
The United States ◽  
Temperature Correction ◽  
Physical Parameters ◽  
Correction Coefficient ◽  
Prototype System ◽  
United States Department ◽  
Very High Frequency ◽  
Grain Moisture ◽  
University Of Budapest ◽  
Improved Accuracy

The Unified Grain Moisture Algorithm is capable of improved accuracy and allows the combination of many grain types into a single “unified calibration”. The purposes of this research were to establish processes for determining unifying parameters from the chemical and physical properties of grains. The data used in this research were obtained as part of the United States Department of Agriculture-Grain Inspection, Packers and Stockyards Administration's Annual Moisture Calibration Study. More than 5,000 grain samples were tested with a Hewlett-Packard 4291A Material/Impedance Analyzer. Temperature tests were done with a Very High Frequency prototype system at Corvinus University of Budapest. Typical chemical and physical parameters for each of the major grain types were obtained from the literature. Data were analyzed by multivariate chemometric methods. One of the most important unifying parameters (Slope) and the temperature correction coefficient were successfully modeled. The Offset and Translation unifying parameters were not modeled successfully, but these parameters can be estimated relatively easily through limited grain tests.

Photovoltaics in the United States Department of Defense

1996 ◽  
Author(s):  
J. F. Hoelscher ◽  
R. Ducey ◽  
G. D. Smith ◽  
L. W. Strother ◽  
C. Combs
Keyword(s):  
United States ◽  
Department Of Defense ◽  
The United States ◽  
United States Department ◽  
States Department

The Difficulties and Promise of an Interagency Public Information Campaign for Water Quality Issues

1993 ◽  
Vol 28 (3-5) ◽  
pp. 65-68
Author(s):  
Michelle Miller
Keyword(s):  
Water Quality ◽  
Public Information ◽  
The United States ◽  
United States Department ◽  
Information Campaign ◽  
Department Of Agriculture ◽  
Voluntary Programs ◽  
University Of Wisconsin ◽  
Quality Issues ◽  
State And Local

The following case study addresses the difficulties and promise of developing a statewide interagency public information campaign to raise general awareness of water quality issues and governmental programs to address them. Due to only moderate success of voluntary programs to curb nonpoint source pollution, agencies are looking toward information and education programs to motivate the public toward conservation behavior. One of the biggest obstacles in developing an effective information/education program is institutional barriers to interagency cooperation, mirroring difficulties local conservationists encounter in their work to restore and maintain water quality at the watershed level. Cooperation between federal agencies, and resource commitment to public information is necessary at the federal level, as well as state and local levels. Agencies involved to date include the United States Department of Agriculture-Soil Conservation Service; Wisconsin State Departments of Natural Resources, and Agriculture, Trade and Consumer Protection and Administration; University of Wisconsin-Extension; Wisconsin Land Conservation Association.

An Overview of the Direct Energy Conversion Proof of Principle Power Production Program

2004 ◽  
Author(s):  
D. King ◽  
G. Rochau ◽  
D. Oscar ◽  
C. Morrow ◽  
P. Tsvetkov ◽  
...  
Keyword(s):  
Energy Conversion ◽  
The United States ◽  
Department Of Energy ◽  
Future Research ◽  
United States Department ◽  
Commercial Development ◽  
Direct Energy Conversion ◽  
Project Description ◽  
Direct Energy ◽  
Proof Of Principle

The United States Department of Energy, Nuclear Energy Research Initiative (NERI) Direct Energy Conversion Proof of Principle (DECPOP) project has as its goal the development of a direct energy conversion process suitable for commercial development. We define direct energy conversion as any fission process that returns usable energy without an intermediate thermal process. A prior Direct Energy Conversion (DEC) project [1] has been completed and indicates that a viable direct energy device is possible if several technological issues can be overcome. The DECPOP program is focusing on two of the issues: charged particle steering and high voltage hold-off. This paper reports on the progress of the DECPOP project. Two prototype concepts are under development: a Fission Electric Cell using magnetic insulation and a Fission Fragment Magnetic Collimator using magnetic fields to direct fission fragments to collectors. Included in this paper are a short project description, an abbreviated summary of the work completed to date, a description of ongoing and future project activities, and a discussion of the potential for future research and development.

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