Understanding Hydrogen Embrittlement/Environment-Sensitive Behavior of Materials via Microstructural Characterization: Advances, Applications and Opportunities

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Sample Preparation Methodologies for In Situ Liquid and Gaseous Cell Analytical Transmission Electron Microscopy of Electropolished Specimens

AbstractIn recent years, an increasing number of studies utilizingin situliquid and/or gaseous cell scanning/transmission electron microscopy (S/TEM) have been reported. Because of the difficulty in the preparation of suitable specimens, these environmental S/TEM studies have been generally limited to studies of nanoscale structured materials such as nanoparticles, nanowires, or sputtered thin films. In this paper, we present two methodologies which have been developed to facilitate the preparation of electron-transparent samples from conventional bulk metals and alloys forin situliquid/gaseous cell S/TEM experiments. These methods take advantage of combining sequential electrochemical jet polishing followed by focused ion beam extraction techniques to create large electron-transparent areas for site-specific observation. As an example, we illustrate the application of this methodology for the preparation ofin situspecimens from a cold-rolled Type 304 austenitic stainless steel sample, which was subsequently examined in both 1 atm of air as well as fully immersed in a H2O environment in the S/TEM followed by hyperspectral imaging. These preparation techniques can be successfully applied as a general procedure for a wide range of metals and alloys, and are suitable for a variety ofin situanalytical S/TEM studies in both aqueous and gaseous environments.</jats:p

Stress corrosion crack initiation testing with tapered specimens in high-temperature water – results of a collaborative research project

The applicability of an accelerated test technique using tapered tensile specimens for investigating thestress corrosion crack (SCC) initiation behaviour of structural materials in high-temperature water wasassessed in the framework of a European collaborative research project (MICRIN – MItigation of CRackINitiation). The main advantage of using a tapered geometry is, that in a single test a stress gradient isobtained through the gauge length, and therefore a stress threshold for SCC initiation can bedetermined in a reasonable timeframe. This method was used to investigate two different materialsthat were known to be susceptible to SCC in light water reactor environment: a high-Si stainlesssteel and a Ni-base weld metal (Alloy 182). The results of the international test programmeconfirmed that the tapered specimen test methodology could be used to identify a SCC initiation stress threshold, albeit that significant scatter was present in the data

The Ursinus Weekly, October 9, 1975

\u2779 elects Delli-Bovi; Jill Leauber fills vacancy • Ursinus hosts family fete • Danforth Foundation offers fellowships • Dept. addition • From the cluttered desk of the U.S.G.A. President • Correction • Editorial: The Fact, after or before • Focus: Dr. Parsons • Overview: Intro. Philosophy • Lions in another Bowl? • The Throwaway children • U.S.G.A. Carnival • Phila. singers open season • Aerosmith: Bedlam • Opportunity for women • Reflections: A letter home • AFC forecast • George McGinnis: $3 million man • Field hockey report • Lebanon Valley crushes Ursinushttps://digitalcommons.ursinus.edu/weekly/1042/thumbnail.jp

Role of the mesoamygdaloid dopamine projection in emotional learning

Amygdala dopamine is crucially involved in the acquisition of Pavlovian associations, as measured via conditioned approach to the location of the unconditioned stimulus (US). However, learning begins before skeletomotor output, so this study assessed whether amygdala dopamine is also involved in earlier 'emotional' learning. A variant of the conditioned reinforcement (CR) procedure was validated where training was restricted to curtail the development of selective conditioned approach to the US location, and effects of amygdala dopamine manipulations before training or later CR testing assessed. Experiment 1a presented a light paired (CS+ group) or unpaired (CS- group) with a US. There were 1, 2 or 10 sessions, 4 trials per session. Then, the US was removed, and two novel levers presented. One lever (CR+) presented the light, and lever pressing was recorded. Experiment 1b also included a tone stimulus. Experiment 2 applied intra-amygdala R(+) 7-OH-DPAT (10 nmol/1.0 A mu l/side) before two training sessions (Experiment 2a) or a CR session (Experiment 2b). For Experiments 1a and 1b, the CS+ group preferred the CR+ lever across all sessions. Conditioned alcove approach during 1 or 2 training sessions or associated CR tests was low and nonspecific. In Experiment 2a, R(+) 7-OH-DPAT before training greatly diminished lever pressing during a subsequent CR test, preferentially on the CR+ lever. For Experiment 2b, R(+) 7-OH-DPAT infusions before the CR test also reduced lever pressing. Manipulations of amygdala dopamine impact the earliest stage of learning in which emotional reactions may be most prevalent