Practice for Recording Environmental Effects for Utilization with A-UGV Test Methods

2019 ◽  
Author(s):  
Keyword(s):  
Environmental Effects ◽  
Test Methods

Combined Effects of Oxidation, Moisture, and Freeze–Thaw on Asphalt Mixtures

2020 ◽  
Vol 2674 (12) ◽  
pp. 409-424
Author(s):  
Rabeea W. Bazuhair ◽  
Isaac L. Howard ◽  
Alex Middleton ◽  
Walter S. Jordan ◽  
Ben C. Cox
Keyword(s):  
Environmental Effects ◽  
Test Methods ◽  
Asphalt Mixtures ◽  
Combined Effects ◽  
Freeze Thaw ◽  
Single Mechanism ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Moisture Conditions ◽  
Aashto T283

This article demonstrates the need to laboratory condition asphalt mixtures to simulate combined environmental effects and then to test unconditioned and conditioned specimens in a manner that damage from these environmental effects can be accumulated. The current state-of-the-art for evaluating asphalt mixtures for use on projects relies on either single-mechanism laboratory conditioning such as oxidation in AASHTO R30, or test methods that cannot accumulate combined effects such as indirect tensile strength in AASHTO T283. This article evaluated hundreds of laboratory-conditioned and field-aged specimens in a hot and no-freeze climate to demonstrate a laboratory conditioning protocol that was able to simulate at least 4 years of field aging, whereas conventional single-mechanism protocols were not. Temperature and moisture conditions within asphalt mixtures were measured over time and used as part of the assessment. The conditioning protocol that showed the most promise consisted of combined exposure to oxidation, moisture, and freeze–thaw mechanisms. The specific combined-effects conditioning protocol used here was 5 days of oxidation at 85°C, 14 days of moisture while submerged in 64°C water, and one freeze–thaw cycle. Other combined-effects protocols could be more suitable for other environments or situations; the main point of this article is that inclusion of oxidation, moisture, and freeze–thaw conditioning into one protocol is promising. The environmental conditions and mechanical property test data presented here suggest the asphalt industry needs to be harsher on mixes during laboratory evaluations, and that combined environmental effects conditioning should be given implementation consideration.

Evaluation of Green Inhibitors

2002 ◽  
Author(s):  
Sankara Papavinasam ◽  
Alex Doiron ◽  
R. Winston Revie
Keyword(s):  
Environmental Effects ◽  
Corrosion Inhibitors ◽  
Test Methods ◽  
Offshore Pipelines ◽  
Internal Corrosion ◽  
Green Inhibitors ◽  
Current Test ◽  
The World ◽  
Green Corrosion Inhibitors ◽  
Selection Of

Producing pipelines are protected from internal corrosion by the application of corrosion inhibitors. Environmental effects of corrosion inhibitors have received increased attention in recent years, especially for offshore pipelines. In response to the drive for more environmentally friendly inhibitors, several “green” corrosion inhibitors have been developed. In the design of new classes of corrosion inhibitors, there is a need to take into account the various environmental regulations that exist. In this paper, the criteria for selecting green inhibitors as used in various part of the world are reviewed. The current test methods, their reproducibility and effectiveness, and their accuracy in relation to the selection of green inhibitors are discussed.

Imaging molecules adsorbed onto electrodes under potential control by scanning probe microscopy

1991 ◽  
Vol 49 ◽  
pp. 376-377 ◽  
Author(s):  
N.J. Tao ◽  
J.A. DeRose ◽  
P.I. Oden ◽  
S.M. Lindsay
Keyword(s):  
Surface Charge ◽  
Environmental Effects ◽  
Scanning Probe Microscopy ◽  
Statistical Significance ◽  
Electrochemical Methods ◽  
Surface Structures ◽  
Scanning Probe ◽  
Potential Control ◽  
Afm Imaging ◽  
Special Circumstances

Clemmer and Beebe have pointed out that surface structures on graphite substrates can be misinterpreted as biopolymer images in STM experiments. We have been using electrochemical methods to react DNA fragments onto gold electrodes for STM and AFM imaging. The adsorbates produced in this way are only homogeneous in special circumstances. Searching an inhomogeneous substrate for ‘desired’ images limits the value of the data. Here, we report on a reversible method for imaging adsorbates. The molecules can be lifted onto and off the substrate during imaging. This leaves no doubt about the validity or statistical significance of the images. Furthermore, environmental effects (such as changes in electrolyte or surface charge) can be investigated easily.

Laboratory proficiency in susceptibility testing of Helicobacter pylori using agar dilution and E test methods

2001 ◽  
Vol 120 (5) ◽  
pp. A586-A587
Author(s):  
L BEST ◽  
S JO ◽  
V VANZANTEN ◽  
D HALDANE ◽  
V LOO ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Susceptibility Testing ◽  
Test Methods ◽  
Agar Dilution
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