Calculations of diffusion and diffusion-limited processes in Ni3Al using accelerated molecular dynamics

We present a systematic microscopic approach to diffusion and diffusion-limited processes in Ni₃Al. These processes have been identified as controlling the deformation of the material under specific circumstances. The embedded atom method calculations are done using kinetic Monte Carlo combined with the Dimer method of finding saddlepoints. We compute the tracer diffusivities as functions of composition and temperature. The comparison with available experiments is good. We find that at temperatures below about 1000 K, the diffusivity is a sharp function of composition, showing a pronounced dip on the Ni-rich side at 76 at.% Ni. This agrees well with experiment, except that the experiments show this structure setting in a temperatures below about 1300 K. We show that the structure arises from the composition dependence of both the vacancy formation energy and pre-exponential of the diffusivity. We also compute the mobility of an anti-phase boundary perpendicular to its plane, and conclude that vacancy-assistance is very plausible. We conclude that the kMC + Dimer method works well for these problems above 700 K but less effectively below, owing to the presence of short-range, low-energy hops that tend to localize the vacancy and lower the efficiency of the calculation.     

ArcFVS:An integration of a Geographic Information System and Forest Vegetation Simulator

This paper presents the design and implementation of an integrated application program called ArcFVS that links the Forest Vegetation Simulator (FVS) and a Geographic Information System (GIS) to realize spatial selection of input files and graphic display of modeling output. Data for testing and running the model came from the U.S. Forest Service's Forest Inventory and Analysis (FIA) Database and were also collected in field surveys in north-central Indiana. ArcFVS 1.0 is designed using the ArcGIS software from the Environmental Systems Research Institute (ESRI) and the Visual Basic for Applications (VBA) programming environment to manipulate ESRI's ArcObjects. The resulting product offers custom functions as commands in a new menu or as tools on a new toolbar. They are used to: select spatially or by attribute the forest plots to be projected by FVS, create the FVS input files for the selected plots and display in a geospatial environment different types of FVS output (text output files, tables with variables of interest and visualization image files). Advantages of ArcFVS 1.0 include the new GIS capabilities, enhanced format translation functions and the standardized programming environment.     

ArcFVS: An integration of a Geographic Information System and Forest Vegetation Simulator

This paper presents the design and implementation of an integrated application program called ArcFVS that links the Forest Vegetation Simulator (FVS) and a Geographic Information System (GIS) to realize spatial selection of input files and graphic display of modeling output. Data for testing and running the model came from the U.S. Forest Service’s Forest Inventory and Analysis (FIA) Database and were also collected in field surveys in north-central Indiana. ArcFVS 1.0 is designed using the ArcGIS software from the Environmental Systems Research Institute (ESRI) and the Visual Basic for Applications (VBA) programming environment to manipulate ESRI’s ArcObjects. The resulting product offers custom functions as commands in a new menu or as tools on a new toolbar. They are used to: select spatially or by attribute the forest plots to be projected by FVS, create the FVS input files for the selected plots and display in a geospatial environment different types of FVS output (text output files, tables with variables of interest and visualization image files). Advantages of ArcFVS 1.0 include the new GIS capabilities, enhanced format translation functions and the standardized programming environment.     

A Critique of Relational Psychoanalysis.

Psychoanalysis today is largely a psychology of consciousness: Post- and neo-Freudians form a marginalized community within North America in comparison to contemporary relational and intersubjective theorists, who emphasize the phenomenology of lived conscious experience, dyadic attachments, affective attunement, social construction, and mutual recognition over the role of insight and interpretation. Despite the rich historical terrain of theoretical variation and advance, many contemporary approaches have displaced the primacy of the unconscious. Notwithstanding the theoretical hairsplitting that historically occurs across the psychoanalytic domain, one is beginning to see with increasing force and clarity what S. Mitchell and L. Aron (1999) referred to as the emergence of a new tradition, namely, relational psychoanalysis. Having its edifice in early object relations theory, the British middle school and American interpersonal traditions, and self psychology, relationality is billed as "a distinctly new tradition" (Mitchell & Aron, 1999, p. x). What is being labeled as the American middle group of psychoanalysis (C. Spezzano, 1997), relational and intersubjective theory have taken center stage. It may be argued, however, that contemporary relational and intersubjective perspectives have failed to be properly critiqued from within their own school of discourse. The scope of this article is largely preoccupied with tracing (a) the philosophical underpinnings of contemporary relational theory, (b) its theoretical relation to traditional psychoanalytic thought, (c) clinical implications for therapeutic practice, and (d) its intersection with points of consilience that emerge from these traditions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparing the effects of text size and format on the readibility of computer-displayed Times New Roman and Arial text

Times New Roman and Arial typefaces in 10- and 12-point, dot-matrix and anti-aliased format conditions were compared for readability (accuracy, reading speed, and accuracy/reading speed), as well as perceptions of typeface legibility, sharpness, ease of reading, and general preference. In assessing readability, the 10-point anti-aliased Arial typeface was read slower than the other type conditions. Examining perceptions of typeface legibility, sharpness, and ease of reading detected significant effects for typeface, size, and format. Overall, the 12-point dot-matrix Arial typeface was preferred to the other typefaces. Recommendations for appropriate typeface combinations for computer-displayed text are discussed.     

A New Navigation Method for an Automatic Guided Vehicle

This paper presents a new navigation method for an automatic guided vehicle (AGV). This method utilizes a new navigation and control scheme based on searching points on an arc. Safety measure indices are defined and are generated from the output of a fuzzy neural network which define the actions the AGV is to take when in the presence of obstacles. The proposed algorithm integrates several functions required for automatic guided vehicle navigation and tracking control and it exhibits satisfactory performance when maneuvering in complex environments. The automatic guided vehicle with this navigation control system not only can quickly process environmental information, but also can efficiently avoid dynamic or static obstacles, and reach targets safely and reliably. Extensive simulation and experimental results demonstrate the effectiveness and correct behavior of this scheme. © 2004 Wiley Periodicals, Inc.     

Eurocorr 2013: ‘For a Blue Sky’ - part 3

The 2013 Eurocorr meeting was held at the Estoril Congress Centre in Estoril, near Lisbon, Portugal from 1–5^th September 2013. The focus of the meeting was ‘For a Blue Sky’. The meeting attracted over 870 delegates from 60 countries and over 300 papers and 200 posters were presented during the 27 sessions and 6 workshops. Parts 1–4 of this report will review the technical sessions over four issues with sessions on corrosion of steel in concrete, corrosion in oil and gas production, corrosion in the refinery industry, corrosion in carbon capture and storage applications, corrosion reliability of electronics devices covered in this part.     

Avalanches on a conical bead pile: scaling with tuning parameters

Uniform spherical beads were used to explore the scaling behavior of a granular system near its critical angle of repose on a conical 3D bead pile. We found two tuning parameters that could take the system to a critical point. The existence of those tuning parameters violates the fundamental assumption of self-organized criticality, which proposed that complex dynamical systems self-organize to a critical point without need for tuning. Our avalanche size distributions were well described by a simple power-law, as is characteristic of a critical point, with the power τ = 1.5 when dropping beads slowly onto the apex of a bead pile from a small height. However, we could also move the system from the critical point using either of two tuning parameters: the height from which the beads fell onto the top of the pile or the region over which the beads struck the pile. As the drop height increased, the system did not reach the critical point yet the resulting distributions were independent of the bead mass, coefficient of friction, or coefficient of restitution. All our apex-dropping distributions for any type of bead (glass, stainless steel, zirconium) showed universality by scaling onto a common curve with τ = 1.5 and σ =?1.0, where 1/σ is the power of the tuning parameter. From independent calculations using the moments of the distribution, we find values for τ = 1.6 ± 0.1 and σ =?0.91 ± 0.15. When beads were dropped across the surface of the pile instead of solely on the apex, then the system also moved from the critical point and again the avalanche size distributions fell on a common curve when scaled similarly using the same values of τ and σ. We also observed that an hcp structure on the base of the pile caused an emergent structure in the pile that had six faces with some fcc or hcp structure; this structure did not affect the distribution of avalanche sizes.