Effect of microstructure and composition on hydrogen permeation in X70 pipeline steels

The influence of microstructure and composition on permeation of hydrogen in 1.2 and 0.5 wt.% Mn X70 pipeline steels after different processing was investigated using an electrochemical permeation technique. For 1.2 wt.% Mn (standard Mn) steel, the microstructure of normalised transfer bar was coarse equiaxed ferrite grains. This sample exhibited the highest diffusivity, followed by transfer bar, with a mixed ferriteebainitic ferrite microstructure; and hot rolled strip, with fine elongated ferrite grains. The 0.5 wt.% Mn (medium Mn) strip displayed lower diffusivity than the 1.2 wt.% Mn strip, due to hydrogen trapping by finer ferrite grains and a higher density of carbonitride precipitates. Moreover, the medium Mn strip exhibited a uniform microstructure and consequently similar diffusion coefficients for the edge and centreline regions, whereas the finer grains of the edge region of the standard Mn strip resulted in a lower diffusivity than the centreline region. Copyright © 2012, Hydrogen Energy Publications, LLC

2D modelling of the effect of grain size on hydrogen diffusion in X70 steel

Grain boundaries and triple junctions are the most favoured hydrogen trapping sites in the microstructure as they have the lowest trapping activation energy. To study the effect of these trapping sites, different microstructures with different surface ratio of grain boundaries were generated. In order to do this, hydrogen diffusion in both grains and grain boundaries was modelled using Cellular Automaton technique combined with the finite difference method. The simulation was implemented in two-dimensions (2D) in both grains and grain boundaries to highlight the significance of grain boundaries in hydrogen diffusion. The developed model was validated by comparing the simulation results with the experimental outcomes of hydrogen permeability measurements in X70 pipeline steel having different grain sizes. The results revealed that grain size (grain boundary fraction) has a two-fold influence on the diffusion rate, that is, in both very fine and very coarse microstructures diffusion rates are slower than for an optimum intermediate grain size

Does Instructor Type Matter? Undergraduate Student Perception of Graduate Teaching Assistants and Professors

Graduate teaching assistants (GTAs) are used extensively as instructors in higher education, yet their status and authority as teachers may be unclear to undergraduates, to administrators, and even to the GTAs themselves. This study explored undergraduate perception of classroom instruction by GTAs and professors to identify factors unique to each type of instructor versus the type of classes they teach. Data collection was via an online survey composed of subscales from two validated instruments, as well as one open-ended question asking students to compare the same class taught by a professor versus a GTA. Quantitative and qualitative results indicated that some student instructional perceptions are specific to instructor type, and not class type. For example, regardless of type of class, professors are perceived as being confident, in control, organized, experienced, knowledgeable, distant, formal, strict, hard, boring, and respected. Conversely, GTAs are perceived as uncertain, hesitant, nervous, relaxed, laid-back, engaging, interactive, relatable, understanding, and able to personalize teaching. Overall, undergraduates seem to perceive professors as having more knowledge and authority over the curriculum, but enjoy the instructional style of GTAs. The results of this study will be used to make recommendations for GTA professional development programs

The globalization of intellectual property right: much ado about nothing?

Book synopsis: First handbook for the discipline of IR concerning science and technology Features well-known scholars from various disciplines Presents interviews about the core themes of the book Offers a methodological toolbox for experts and students An increasing number of scholars have begun to see science and technology as relevant issues in International Relations (IR), acknowledging the impact of material elements, technical instruments, and scientific practices on international security, statehood, and global governance. This two-volume collection brings the debate about science and technology to the center of International Relations. It shows how integrating science and technology translates into novel analytical frameworks, conceptual approaches and empirical puzzles, and thereby offers a state-of-the-art review of various methodological and theoretical ways in which sciences and technologies matter for the study of international affairs and world politics. The authors not only offer a set of practical examples of research frameworks for experts and students alike, but also propose a conceptual space for interdisciplinary learning in order to improve our understanding of the global politics of science and technology. The second volume raises a plethora of issue areas, actors, and cases under the umbrella notion techno-politics. Distinguishing between interactional and co-productive perspectives, it outlines a toolbox of analytical frameworks that transcend technological determinism and social constructivism

Does One Size Fit All? Patents, the Right to Health and Access to Medicines

The question posed in this article is whether the right to health and patents conflict or coexist. This question is examined from the perspective of the issue of access to affordable medicines in developing countries focusing on the right to health as set out in the ICESCR and patent standards (and flexibilities) as required by the TRIPS Agreement. In the strict sense, there is no conflict between the right to health and patents. ICESCR and TRIPS do not contain mutually exclusive obligations. Yet, it is shown that tension between the two does exist. There are a number of ways in which such tension can be resolved. The UN Sub-Commission for the Promotion and Protection of Human Rights has contended that human rights should enjoy primacy over patents, yet there is no evidence to suggest that the right to health and/ or access to essential medicines are considered prioritised norms under international law. The WTO disagrees and views IPRs and human rights as complementary. In international law there is a strong presumption against conflict. In line with the principle of systemic integration a good faith interpretation of the relevant WTO and human rights provisions should lead to a reading of TRIPS' obligations which is coherent with human rights law. However, this balancing act must also take place at the domestic level and the success of such a coexistence approach, namely whether (developing) states are able to strike a balance between access to medicines and patent protection, will depend much on the actual implementation and interpretation by states. Consequently, some examples of state practice regarding the interpretation and implementation of TRIPS in light of the right to health are highlighted